LeetCode Problems Library

All LeetCode Problems

• 207. Course Schedule - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 134. Gas Station - MediumTopics: Array, Greedy
• 412. Fizz Buzz - EasyTopics: Math, String, Simulation
• 1. Two Sum - EasyTopics: Array, Hash Table
• 206. Reverse Linked List - EasyTopics: Linked List, Recursion
• 279. Perfect Squares - MediumTopics: Math, Dynamic Programming, Breadth-First Search
• 4. Median of Two Sorted Arrays - HardTopics: Array, Binary Search, Divide and Conquer
• 3. Longest Substring Without Repeating Characters - MediumTopics: Hash Table, String, Sliding Window
• 5. Longest Palindromic Substring - MediumTopics: Two Pointers, String, Dynamic Programming
• 792. Binary Search - EasyTopics: Array, Binary Search
• 146. LRU Cache - MediumTopics: Hash Table, Linked List, Design, Doubly-Linked List
• 118. Pascal's Triangle - EasyTopics: Array, Dynamic Programming
• 202. Happy Number - EasyTopics: Hash Table, Math, Two Pointers
• 127. Word Ladder - HardTopics: Hash Table, String, Breadth-First Search
• 53. Maximum Subarray - MediumTopics: Array, Divide and Conquer, Dynamic Programming
• 144. Binary Tree Preorder Traversal - EasyTopics: Stack, Tree, Depth-First Search, Binary Tree
• 300. Longest Increasing Subsequence - MediumTopics: Array, Binary Search, Dynamic Programming
• 94. Binary Tree Inorder Traversal - EasyTopics: Stack, Tree, Depth-First Search, Binary Tree
• 121. Best Time to Buy and Sell Stock - EasyTopics: Array, Dynamic Programming
• 1250. Longest Common Subsequence - MediumTopics: String, Dynamic Programming
• 15. 3Sum - MediumTopics: Array, Two Pointers, Sorting
• 226. Invert Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 322. Coin Change - MediumTopics: Array, Dynamic Programming, Breadth-First Search
• 49. Group Anagrams - MediumTopics: Array, Hash Table, String, Sorting
• 200. Number of Islands - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 560. Subarray Sum Equals K - MediumTopics: Array, Hash Table, Prefix Sum
• 77. Combinations - MediumTopics: Backtracking
• 55. Jump Game - MediumTopics: Array, Dynamic Programming, Greedy
• 236. Lowest Common Ancestor of a Binary Tree - MediumTopics: Tree, Depth-First Search, Binary Tree
• 347. Top K Frequent Elements - MediumTopics: Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect
• 88. Merge Sorted Array - EasyTopics: Array, Two Pointers, Sorting
• 54. Spiral Matrix - MediumTopics: Array, Matrix, Simulation
• 76. Minimum Window Substring - HardTopics: Hash Table, String, Sliding Window
• 18. 4Sum - MediumTopics: Array, Two Pointers, Sorting
• 79. Word Search - MediumTopics: Array, String, Backtracking, Depth-First Search, Matrix
• 344. Reverse String - EasyTopics: Two Pointers, String
• 21. Merge Two Sorted Lists - EasyTopics: Linked List, Recursion
• 46. Permutations - MediumTopics: Array, Backtracking
• 409. Longest Palindrome - EasyTopics: Hash Table, String, Greedy
• 11. Container With Most Water - MediumTopics: Array, Two Pointers, Greedy
• 145. Binary Tree Postorder Traversal - EasyTopics: Stack, Tree, Depth-First Search, Binary Tree
• 20. Valid Parentheses - EasyTopics: String, Stack
• 128. Longest Consecutive Sequence - MediumTopics: Array, Hash Table, Union Find
• 152. Maximum Product Subarray - MediumTopics: Array, Dynamic Programming
• 70. Climbing Stairs - EasyTopics: Math, Dynamic Programming, Memoization
• 75. Sort Colors - MediumTopics: Array, Two Pointers, Sorting
• 1014. K Closest Points to Origin - MediumTopics: Array, Math, Divide and Conquer, Geometry, Sorting, Heap (Priority Queue), Quickselect
• 141. Linked List Cycle - EasyTopics: Hash Table, Linked List, Two Pointers
• 66. Plus One - EasyTopics: Array, Math
• 102. Binary Tree Level Order Traversal - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 56. Merge Intervals - MediumTopics: Array, Sorting
• 23. Merge k Sorted Lists - HardTopics: Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort
• 721. Accounts Merge - MediumTopics: Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union Find, Sorting
• 14. Longest Common Prefix - EasyTopics: Array, String, Trie
• 42. Trapping Rain Water - HardTopics: Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack
• 151. Reverse Words in a String - MediumTopics: Two Pointers, String
• 98. Validate Binary Search Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 460. LFU Cache - HardTopics: Hash Table, Linked List, Design, Doubly-Linked List
• 48. Rotate Image - MediumTopics: Array, Math, Matrix
• 125. Valid Palindrome - EasyTopics: Two Pointers, String
• 803. Cheapest Flights Within K Stops - MediumTopics: Dynamic Programming, Depth-First Search, Breadth-First Search, Graph, Heap (Priority Queue), Shortest Path
• 110. Balanced Binary Tree - EasyTopics: Tree, Depth-First Search, Binary Tree
• 374. Guess Number Higher or Lower - EasyTopics: Binary Search, Interactive
• 9. Palindrome Number - EasyTopics: Math
• 516. Longest Palindromic Subsequence - MediumTopics: String, Dynamic Programming
• 169. Majority Element - EasyTopics: Array, Hash Table, Divide and Conquer, Sorting, Counting
• 543. Diameter of Binary Tree - EasyTopics: Tree, Depth-First Search, Binary Tree
• 733. Flood Fill - EasyTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 123. Best Time to Buy and Sell Stock III - HardTopics: Array, Dynamic Programming
• 238. Product of Array Except Self - MediumTopics: Array, Prefix Sum
• 26. Remove Duplicates from Sorted Array - EasyTopics: Array, Two Pointers
• 72. Edit Distance - MediumTopics: String, Dynamic Programming
• 162. Find Peak Element - MediumTopics: Array, Binary Search
• 179. Largest Number - MediumTopics: Array, String, Greedy, Sorting
• 898. Transpose Matrix - EasyTopics: Array, Matrix, Simulation
• 468. Validate IP Address - MediumTopics: String
• 17. Letter Combinations of a Phone Number - MediumTopics: Hash Table, String, Backtracking
• 268. Missing Number - EasyTopics: Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting
• 199. Binary Tree Right Side View - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 19. Remove Nth Node From End of List - MediumTopics: Linked List, Two Pointers
• 378. Kth Smallest Element in a Sorted Matrix - MediumTopics: Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
• 295. Find Median from Data Stream - HardTopics: Two Pointers, Design, Sorting, Heap (Priority Queue), Data Stream
• 208. Implement Trie (Prefix Tree) - MediumTopics: Hash Table, String, Design, Trie
• 8. String to Integer (atoi) - MediumTopics: String
• 210. Course Schedule II - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 1013. Fibonacci Number - EasyTopics: Math, Dynamic Programming, Recursion, Memoization
• 104. Maximum Depth of Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 167. Two Sum II - Input Array Is Sorted - MediumTopics: Array, Two Pointers, Binary Search
• 630. Course Schedule III - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 124. Binary Tree Maximum Path Sum - HardTopics: Dynamic Programming, Tree, Depth-First Search, Binary Tree
• 289. Game of Life - MediumTopics: Array, Matrix, Simulation
• 1029. Vertical Order Traversal of a Binary Tree - HardTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Sorting, Binary Tree
• 41. First Missing Positive - HardTopics: Array, Hash Table
• 215. Kth Largest Element in an Array - MediumTopics: Array, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
• 39. Combination Sum - MediumTopics: Array, Backtracking
• 383. Ransom Note - EasyTopics: Hash Table, String, Counting
• 33. Search in Rotated Sorted Array - MediumTopics: Array, Binary Search
• 801. Is Graph Bipartite? - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 138. Copy List with Random Pointer - MediumTopics: Hash Table, Linked List
• 67. Add Binary - EasyTopics: Math, String, Bit Manipulation, Simulation
• 7. Reverse Integer - MediumTopics: Math
• 190. Reverse Bits - EasyTopics: Divide and Conquer, Bit Manipulation
• 222. Count Complete Tree Nodes - EasyTopics: Binary Search, Bit Manipulation, Tree, Binary Tree
• 1046. Max Consecutive Ones III - MediumTopics: Array, Binary Search, Sliding Window, Prefix Sum
• 235. Lowest Common Ancestor of a Binary Search Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 91. Decode Ways - MediumTopics: String, Dynamic Programming
• 108. Convert Sorted Array to Binary Search Tree - EasyTopics: Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
• 239. Sliding Window Maximum - HardTopics: Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
• 416. Partition Equal Subset Sum - MediumTopics: Array, Dynamic Programming
• 122. Best Time to Buy and Sell Stock II - MediumTopics: Array, Dynamic Programming, Greedy
• 450. Delete Node in a BST - MediumTopics: Tree, Binary Search Tree, Binary Tree
• 234. Palindrome Linked List - EasyTopics: Linked List, Two Pointers, Stack, Recursion
• 242. Valid Anagram - EasyTopics: Hash Table, String, Sorting
• 153. Find Minimum in Rotated Sorted Array - MediumTopics: Array, Binary Search
• 442. Find All Duplicates in an Array - MediumTopics: Array, Hash Table
• 34. Find First and Last Position of Element in Sorted Array - MediumTopics: Array, Binary Search
• 25. Reverse Nodes in k-Group - HardTopics: Linked List, Recursion
• 224. Basic Calculator - HardTopics: Math, String, Stack, Recursion
• 65. Valid Number - HardTopics: String
• 83. Remove Duplicates from Sorted List - EasyTopics: Linked List
• 518. Coin Change II - MediumTopics: Array, Dynamic Programming
• 105. Construct Binary Tree from Preorder and Inorder Traversal - MediumTopics: Array, Hash Table, Divide and Conquer, Tree, Binary Tree
• 155. Min Stack - MediumTopics: Stack, Design
• 529. Minesweeper - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 2373. Apply Discount to Prices - MediumTopics: String
• 198. House Robber - MediumTopics: Array, Dynamic Programming
• 212. Word Search II - HardTopics: Array, String, Backtracking, Trie, Matrix
• 2406. Decode the Message - EasyTopics: Hash Table, String
• 567. Permutation in String - MediumTopics: Hash Table, Two Pointers, String, Sliding Window
• 193. Valid Phone Numbers - EasyTopics: Shell
• 114. Flatten Binary Tree to Linked List - MediumTopics: Linked List, Stack, Tree, Depth-First Search, Binary Tree
• 31. Next Permutation - MediumTopics: Array, Two Pointers
• 22. Generate Parentheses - MediumTopics: String, Dynamic Programming, Backtracking
• 13. Roman to Integer - EasyTopics: Hash Table, Math, String
• 176. Second Highest Salary - MediumTopics: Database
• 1036. Rotting Oranges - MediumTopics: Array, Breadth-First Search, Matrix
• 189. Rotate Array - MediumTopics: Array, Math, Two Pointers
• 133. Clone Graph - MediumTopics: Hash Table, Depth-First Search, Breadth-First Search, Graph
• 747. Min Cost Climbing Stairs - EasyTopics: Array, Dynamic Programming
• 653. Two Sum IV - Input is a BST - EasyTopics: Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
• 69. Sqrt(x) - EasyTopics: Math, Binary Search
• 160. Intersection of Two Linked Lists - EasyTopics: Hash Table, Linked List, Two Pointers
• 36. Valid Sudoku - MediumTopics: Array, Hash Table, Matrix
• 148. Sort List - MediumTopics: Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort
• 6. Zigzag Conversion - MediumTopics: String
• 78. Subsets - MediumTopics: Array, Backtracking, Bit Manipulation
• 106. Construct Binary Tree from Inorder and Postorder Traversal - MediumTopics: Array, Hash Table, Divide and Conquer, Tree, Binary Tree
• 227. Basic Calculator II - MediumTopics: Math, String, Stack
• 297. Serialize and Deserialize Binary Tree - HardTopics: String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Tree
• 621. Task Scheduler - MediumTopics: Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Counting
• 496. Next Greater Element I - EasyTopics: Array, Hash Table, Stack, Monotonic Stack
• 43. Multiply Strings - MediumTopics: Math, String, Simulation
• 572. Subtree of Another Tree - EasyTopics: Tree, Depth-First Search, String Matching, Binary Tree, Hash Function
• 309. Best Time to Buy and Sell Stock with Cooldown - MediumTopics: Array, Dynamic Programming
• 1019. Squares of a Sorted Array - EasyTopics: Array, Two Pointers, Sorting
• 945. Snakes and Ladders - MediumTopics: Array, Breadth-First Search, Matrix
• 1137. Height Checker - EasyTopics: Array, Sorting, Counting Sort
• 315. Count of Smaller Numbers After Self - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 68. Text Justification - HardTopics: Array, String, Simulation
• 2479. Meeting Rooms III - HardTopics: Array, Hash Table, Sorting, Heap (Priority Queue), Simulation
• 940. Fruit Into Baskets - MediumTopics: Array, Hash Table, Sliding Window
• 287. Find the Duplicate Number - MediumTopics: Array, Two Pointers, Binary Search, Bit Manipulation
• 787. Sliding Puzzle - HardTopics: Array, Dynamic Programming, Backtracking, Breadth-First Search, Memoization, Matrix
• 438. Find All Anagrams in a String - MediumTopics: Hash Table, String, Sliding Window
• 355. Design Twitter - MediumTopics: Hash Table, Linked List, Design, Heap (Priority Queue)
• 965. Unique Email Addresses - EasyTopics: Array, Hash Table, String
• 720. Longest Word in Dictionary - MediumTopics: Array, Hash Table, String, Trie, Sorting
• 735. Asteroid Collision - MediumTopics: Array, Stack, Simulation
• 16. 3Sum Closest - MediumTopics: Array, Two Pointers, Sorting
• 292. Nim Game - EasyTopics: Math, Brainteaser, Game Theory
• 3934. Coupon Code Validator - EasyTopics: Array, Hash Table, String, Sorting
• 2. Add Two Numbers - MediumTopics: Linked List, Math, Recursion
• 62. Unique Paths - MediumTopics: Math, Dynamic Programming, Combinatorics
• 1352. Maximum Profit in Job Scheduling - HardTopics: Array, Binary Search, Dynamic Programming, Sorting
• 424. Longest Repeating Character Replacement - MediumTopics: Hash Table, String, Sliding Window
• 741. Cherry Pickup - HardTopics: Array, Dynamic Programming, Matrix
• 230. Kth Smallest Element in a BST - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 912. Random Pick with Weight - MediumTopics: Array, Math, Binary Search, Prefix Sum, Randomized
• 394. Decode String - MediumTopics: String, Stack, Recursion
• 883. Car Fleet - MediumTopics: Array, Stack, Sorting, Monotonic Stack
• 387. First Unique Character in a String - EasyTopics: Hash Table, String, Queue, Counting
• 92. Reverse Linked List II - MediumTopics: Linked List
• 51. N-Queens - HardTopics: Array, Backtracking
• 784. Insert into a Binary Search Tree - MediumTopics: Tree, Binary Search Tree, Binary Tree
• 817. Design HashMap - EasyTopics: Array, Hash Table, Linked List, Design, Hash Function
• 45. Jump Game II - MediumTopics: Array, Dynamic Programming, Greedy
• 380. Insert Delete GetRandom O(1) - MediumTopics: Array, Hash Table, Math, Design, Randomized
• 71. Simplify Path - MediumTopics: String, Stack
• 231. Power of Two - EasyTopics: Math, Bit Manipulation, Recursion
• 329. Longest Increasing Path in a Matrix - HardTopics: Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph, Topological Sort, Memoization, Matrix
• 217. Contains Duplicate - EasyTopics: Array, Hash Table, Sorting
• 301. Remove Invalid Parentheses - HardTopics: String, Backtracking, Breadth-First Search
• 1570. Final Prices With a Special Discount in a Shop - EasyTopics: Array, Stack, Monotonic Stack
• 136. Single Number - EasyTopics: Array, Bit Manipulation
• 209. Minimum Size Subarray Sum - MediumTopics: Array, Binary Search, Sliding Window, Prefix Sum
• 1708. Design Parking System - EasyTopics: Design, Simulation, Counting
• 103. Binary Tree Zigzag Level Order Traversal - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 908. Middle of the Linked List - EasyTopics: Linked List, Two Pointers
• 822. Unique Morse Code Words - EasyTopics: Array, Hash Table, String
• 175. Combine Two Tables - EasyTopics: Database
• 129. Sum Root to Leaf Numbers - MediumTopics: Tree, Depth-First Search, Binary Tree
• 37. Sudoku Solver - HardTopics: Array, Hash Table, Backtracking, Matrix
• 27. Remove Element - EasyTopics: Array, Two Pointers
• 494. Target Sum - MediumTopics: Array, Dynamic Programming, Backtracking
• 12. Integer to Roman - MediumTopics: Hash Table, Math, String
• 32. Longest Valid Parentheses - HardTopics: String, Dynamic Programming, Stack
• 507. Perfect Number - EasyTopics: Math
• 753. Open the Lock - MediumTopics: Array, Hash Table, String, Breadth-First Search
• 278. First Bad Version - EasyTopics: Binary Search, Interactive
• 180. Consecutive Numbers - MediumTopics: Database
• 47. Permutations II - MediumTopics: Array, Backtracking, Sorting
• 139. Word Break - MediumTopics: Array, Hash Table, String, Dynamic Programming, Trie, Memoization
• 658. Find K Closest Elements - MediumTopics: Array, Two Pointers, Binary Search, Sliding Window, Sorting, Heap (Priority Queue)
• 101. Symmetric Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 403. Frog Jump - HardTopics: Array, Dynamic Programming
• 336. Palindrome Pairs - HardTopics: Array, Hash Table, String, Trie
• 1960. Check if the Sentence Is Pangram - EasyTopics: Hash Table, String
• 443. String Compression - MediumTopics: Two Pointers, String
• 10. Regular Expression Matching - HardTopics: String, Dynamic Programming, Recursion
• 838. Design Linked List - MediumTopics: Linked List, Design
• 225. Implement Stack using Queues - EasyTopics: Stack, Design, Queue
• 2047. Find a Peak Element II - MediumTopics: Array, Binary Search, Matrix
• 3613. Maximize Amount After Two Days of Conversions - MediumTopics: Array, String, Depth-First Search, Breadth-First Search, Graph
• 349. Intersection of Two Arrays - EasyTopics: Array, Hash Table, Two Pointers, Binary Search, Sorting
• 172. Factorial Trailing Zeroes - MediumTopics: Math
• 119. Pascal's Triangle II - EasyTopics: Array, Dynamic Programming
• 2759. Flatten Deeply Nested Array - MediumTopics:
• 523. Continuous Subarray Sum - MediumTopics: Array, Hash Table, Math, Prefix Sum
• 647. Palindromic Substrings - MediumTopics: Two Pointers, String, Dynamic Programming
• 456. 132 Pattern - MediumTopics: Array, Binary Search, Stack, Monotonic Stack, Ordered Set
• 341. Flatten Nested List Iterator - MediumTopics: Stack, Tree, Depth-First Search, Design, Queue, Iterator
• 232. Implement Queue using Stacks - EasyTopics: Stack, Design, Queue
• 617. Merge Two Binary Trees - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2041. The Latest Login in 2020 - EasyTopics: Database
• 1428. Jump Game III - MediumTopics: Array, Depth-First Search, Breadth-First Search
• 143. Reorder List - MediumTopics: Linked List, Two Pointers, Stack, Recursion
• 111. Minimum Depth of Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 326. Power of Three - EasyTopics: Math, Recursion
• 29. Divide Two Integers - MediumTopics: Math, Bit Manipulation
• 503. Next Greater Element II - MediumTopics: Array, Stack, Monotonic Stack
• 120. Triangle - MediumTopics: Array, Dynamic Programming
• 948. Sort an Array - MediumTopics: Array, Divide and Conquer, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
• 854. Making A Large Island - HardTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 794. Swim in Rising Water - HardTopics: Array, Binary Search, Depth-First Search, Breadth-First Search, Union Find, Heap (Priority Queue), Matrix
• 1646. Kth Missing Positive Number - EasyTopics: Array, Binary Search
• 126. Word Ladder II - HardTopics: Hash Table, String, Backtracking, Breadth-First Search
• 1447. Jump Game IV - HardTopics: Array, Hash Table, Breadth-First Search
• 171. Excel Sheet Column Number - EasyTopics: Math, String
• 680. Valid Palindrome II - EasyTopics: Two Pointers, String, Greedy
• 2021. Remove All Occurrences of a Substring - MediumTopics: String, Stack, Simulation
• 952. Word Subsets - MediumTopics: Array, Hash Table, String
• 131. Palindrome Partitioning - MediumTopics: String, Dynamic Programming, Backtracking
• 97. Interleaving String - MediumTopics: String, Dynamic Programming
• 96. Unique Binary Search Trees - MediumTopics: Math, Dynamic Programming, Tree, Binary Search Tree, Binary Tree
• 1343. Dice Roll Simulation - HardTopics: Array, Dynamic Programming
• 350. Intersection of Two Arrays II - EasyTopics: Array, Hash Table, Two Pointers, Binary Search, Sorting
• 290. Word Pattern - EasyTopics: Hash Table, String
• 81. Search in Rotated Sorted Array II - MediumTopics: Array, Binary Search
• 433. Minimum Genetic Mutation - MediumTopics: Hash Table, String, Breadth-First Search
• 28. Find the Index of the First Occurrence in a String - EasyTopics: Two Pointers, String, String Matching
• 777. Toeplitz Matrix - EasyTopics: Array, Matrix
• 213. House Robber II - MediumTopics: Array, Dynamic Programming
• 205. Isomorphic Strings - EasyTopics: Hash Table, String
• 74. Search a 2D Matrix - MediumTopics: Array, Binary Search, Matrix
• 3267. Find Longest Special Substring That Occurs Thrice I - MediumTopics: Hash Table, String, Binary Search, Sliding Window, Counting
• 673. Number of Longest Increasing Subsequence - MediumTopics: Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
• 398. Random Pick Index - MediumTopics: Hash Table, Math, Reservoir Sampling, Randomized
• 1119. Robot Bounded In Circle - MediumTopics: Math, String, Simulation
• 542. 01 Matrix - MediumTopics: Array, Dynamic Programming, Breadth-First Search, Matrix
• 1285. Balance a Binary Search Tree - MediumTopics: Divide and Conquer, Greedy, Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 283. Move Zeroes - EasyTopics: Array, Two Pointers
• 920. Uncommon Words from Two Sentences - EasyTopics: Hash Table, String, Counting
• 147. Insertion Sort List - MediumTopics: Linked List, Sorting
• 61. Rotate List - MediumTopics: Linked List, Two Pointers
• 2550. Words Within Two Edits of Dictionary - MediumTopics: Array, String, Trie
• 990. Verifying an Alien Dictionary - EasyTopics: Array, Hash Table, String
• 837. Most Common Word - EasyTopics: Array, Hash Table, String, Counting
• 1153. Product Sales Analysis I - EasyTopics: Database
• 420. Strong Password Checker - HardTopics: String, Greedy, Heap (Priority Queue)
• 399. Evaluate Division - MediumTopics: Array, String, Depth-First Search, Breadth-First Search, Union Find, Graph, Shortest Path
• 860. Design Circular Queue - MediumTopics: Array, Linked List, Design, Queue
• 384. Shuffle an Array - MediumTopics: Array, Math, Design, Randomized
• 63. Unique Paths II - MediumTopics: Array, Dynamic Programming, Matrix
• 937. Online Stock Span - MediumTopics: Stack, Design, Monotonic Stack, Data Stream
• 73. Set Matrix Zeroes - MediumTopics: Array, Hash Table, Matrix
• 461. Hamming Distance - EasyTopics: Bit Manipulation
• 223. Rectangle Area - MediumTopics: Math, Geometry
• 188. Best Time to Buy and Sell Stock IV - HardTopics: Array, Dynamic Programming
• 417. Pacific Atlantic Water Flow - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 557. Reverse Words in a String III - EasyTopics: Two Pointers, String
• 2778. Frequency Tracker - MediumTopics: Hash Table, Design
• 182. Duplicate Emails - EasyTopics: Database
• 142. Linked List Cycle II - MediumTopics: Hash Table, Linked List, Two Pointers
• 1559. Cherry Pickup II - HardTopics: Array, Dynamic Programming, Matrix
• 89. Gray Code - MediumTopics: Math, Backtracking, Bit Manipulation
• 3863. Power Grid Maintenance - MediumTopics: Array, Hash Table, Depth-First Search, Breadth-First Search, Union Find, Graph, Heap (Priority Queue), Ordered Set
• 174. Dungeon Game - HardTopics: Array, Dynamic Programming, Matrix
• 434. Number of Segments in a String - EasyTopics: String
• 204. Count Primes - MediumTopics: Array, Math, Enumeration, Number Theory
• 726. Number of Atoms - HardTopics: Hash Table, String, Stack, Sorting
• 893. All Nodes Distance K in Binary Tree - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3847. Minimum Swaps to Sort by Digit Sum - MediumTopics: Array, Hash Table, Sorting
• 80. Remove Duplicates from Sorted Array II - MediumTopics: Array, Two Pointers
• 371. Sum of Two Integers - MediumTopics: Math, Bit Manipulation
• 909. Stone Game - MediumTopics: Array, Math, Dynamic Programming, Game Theory
• 640. Solve the Equation - MediumTopics: Math, String, Simulation
• 140. Word Break II - HardTopics: Array, Hash Table, String, Dynamic Programming, Backtracking, Trie, Memoization
• 525. Contiguous Array - MediumTopics: Array, Hash Table, Prefix Sum
• 1635. Number of Good Pairs - EasyTopics: Array, Hash Table, Math, Counting
• 1414. Shortest Path in a Grid with Obstacles Elimination - HardTopics: Array, Breadth-First Search, Matrix
• 211. Design Add and Search Words Data Structure - MediumTopics: String, Depth-First Search, Design, Trie
• 1171. Shortest Path in Binary Matrix - MediumTopics: Array, Breadth-First Search, Matrix
• 1274. Number of Days Between Two Dates - EasyTopics: Math, String
• 605. Can Place Flowers - EasyTopics: Array, Greedy
• 643. Maximum Average Subarray I - EasyTopics: Array, Sliding Window
• 299. Bulls and Cows - MediumTopics: Hash Table, String, Counting
• 715. Range Module - HardTopics: Design, Segment Tree, Ordered Set
• 2526. Longest Increasing Subsequence II - HardTopics: Array, Divide and Conquer, Dynamic Programming, Binary Indexed Tree, Segment Tree, Queue, Monotonic Queue
• 2552. Maximum Sum of Distinct Subarrays With Length K - MediumTopics: Array, Hash Table, Sliding Window
• 82. Remove Duplicates from Sorted List II - MediumTopics: Linked List, Two Pointers
• 1127. Last Stone Weight - EasyTopics: Array, Heap (Priority Queue)
• 1558. Course Schedule IV - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 978. Valid Mountain Array - EasyTopics: Array
• 454. 4Sum II - MediumTopics: Array, Hash Table
• 137. Single Number II - MediumTopics: Array, Bit Manipulation
• 64. Minimum Path Sum - MediumTopics: Array, Dynamic Programming, Matrix
• 116. Populating Next Right Pointers in Each Node - MediumTopics: Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2444. Longest Ideal Subsequence - MediumTopics: Hash Table, String, Dynamic Programming
• 3892. Best Time to Buy and Sell Stock V - MediumTopics: Array, Dynamic Programming
• 1056. Capacity To Ship Packages Within D Days - MediumTopics: Array, Binary Search
• 650. 2 Keys Keyboard - MediumTopics: Math, Dynamic Programming
• 1411. Convert Binary Number in a Linked List to Integer - EasyTopics: Linked List, Math
• 312. Burst Balloons - HardTopics: Array, Dynamic Programming
• 381. Insert Delete GetRandom O(1) - Duplicates allowed - HardTopics: Array, Hash Table, Math, Design, Randomized
• 99. Recover Binary Search Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 150. Evaluate Reverse Polish Notation - MediumTopics: Array, Math, Stack
• 861. Flipping an Image - EasyTopics: Array, Two Pointers, Bit Manipulation, Matrix, Simulation
• 86. Partition List - MediumTopics: Linked List, Two Pointers
• 2808. Painting the Walls - HardTopics: Array, Dynamic Programming
• 2106. Find Greatest Common Divisor of Array - EasyTopics: Array, Math, Number Theory
• 744. Network Delay Time - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Heap (Priority Queue), Shortest Path
• 923. Super Egg Drop - HardTopics: Math, Binary Search, Dynamic Programming
• 699. Falling Squares - HardTopics: Array, Segment Tree, Ordered Set
• 783. Search in a Binary Search Tree - EasyTopics: Tree, Binary Search Tree, Binary Tree
• 1028. Interval List Intersections - MediumTopics: Array, Two Pointers, Line Sweep
• 485. Max Consecutive Ones - EasyTopics: Array
• 2211. K Radius Subarray Averages - MediumTopics: Array, Sliding Window
• 107. Binary Tree Level Order Traversal II - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 435. Non-overlapping Intervals - MediumTopics: Array, Dynamic Programming, Greedy, Sorting
• 395. Longest Substring with At Least K Repeating Characters - MediumTopics: Hash Table, String, Divide and Conquer, Sliding Window
• 3188. Find Champion I - EasyTopics: Array, Matrix
• 1452. Restaurant Growth - MediumTopics: Database
• 1421. Find Numbers with Even Number of Digits - EasyTopics: Array, Math
• 1128. Remove All Adjacent Duplicates In String - EasyTopics: String, Stack
• 885. Exam Room - MediumTopics: Design, Heap (Priority Queue), Ordered Set
• 954. Maximum Sum Circular Subarray - MediumTopics: Array, Divide and Conquer, Dynamic Programming, Queue, Monotonic Queue
• 1205. Defanging an IP Address - EasyTopics: String
• 1044. Find Common Characters - EasyTopics: Array, Hash Table, String
• 1106. Escape a Large Maze - HardTopics: Array, Hash Table, Depth-First Search, Breadth-First Search
• 3573. Count Substrings That Can Be Rearranged to Contain a String I - MediumTopics: Hash Table, String, Sliding Window
• 975. Range Sum of BST - EasyTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 530. Minimum Absolute Difference in BST - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
• 132. Palindrome Partitioning II - HardTopics: String, Dynamic Programming
• 2035. Count Sub Islands - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 577. Employee Bonus - EasyTopics: Database
• 241. Different Ways to Add Parentheses - MediumTopics: Math, String, Dynamic Programming, Recursion, Memoization
• 1944. Truncate Sentence - EasyTopics: Array, String
• 93. Restore IP Addresses - MediumTopics: String, Backtracking
• 451. Sort Characters By Frequency - MediumTopics: Hash Table, String, Sorting, Heap (Priority Queue), Bucket Sort, Counting
• 3176. Minimum Sum of Mountain Triplets I - EasyTopics: Array
• 807. Custom Sort String - MediumTopics: Hash Table, String, Sorting
• 173. Binary Search Tree Iterator - MediumTopics: Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator
• 44. Wildcard Matching - HardTopics: String, Dynamic Programming, Greedy, Recursion
• 316. Remove Duplicate Letters - MediumTopics: String, Stack, Greedy, Monotonic Stack
• 1263. Number of Dice Rolls With Target Sum - MediumTopics: Dynamic Programming
• 1814. Jump Game VI - MediumTopics: Array, Dynamic Programming, Queue, Heap (Priority Queue), Monotonic Queue
• 684. Redundant Connection - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 2378. Sender With Largest Word Count - MediumTopics: Array, Hash Table, String, Counting
• 724. Find Pivot Index - EasyTopics: Array, Prefix Sum
• 659. Split Array into Consecutive Subsequences - MediumTopics: Array, Hash Table, Greedy, Heap (Priority Queue)
• 528. Swapping Nodes in a Linked List - MediumTopics: Linked List, Two Pointers
• 907. Koko Eating Bananas - MediumTopics: Array, Binary Search
• 328. Odd Even Linked List - MediumTopics: Linked List
• 377. Combination Sum IV - MediumTopics: Array, Dynamic Programming
• 678. Valid Parenthesis String - MediumTopics: String, Dynamic Programming, Stack, Greedy
• 59. Spiral Matrix II - MediumTopics: Array, Matrix, Simulation
• 237. Delete Node in a Linked List - MediumTopics: Linked List
• 679. 24 Game - HardTopics: Array, Math, Backtracking
• 2599. Take K of Each Character From Left and Right - MediumTopics: Hash Table, String, Sliding Window
• 2150. Kth Smallest Product of Two Sorted Arrays - HardTopics: Array, Binary Search
• 154. Find Minimum in Rotated Sorted Array II - HardTopics: Array, Binary Search
• 342. Power of Four - EasyTopics: Math, Bit Manipulation, Recursion
• 856. Consecutive Numbers Sum - HardTopics: Math, Enumeration
• 410. Split Array Largest Sum - HardTopics: Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
• 2868. Continuous Subarrays - MediumTopics: Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
• 457. Circular Array Loop - MediumTopics: Array, Hash Table, Two Pointers
• 1669. Minimum Cost to Cut a Stick - HardTopics: Array, Dynamic Programming, Sorting
• 1272. Invalid Transactions - MediumTopics: Array, Hash Table, String, Sorting
• 1966. Frequency of the Most Frequent Element - MediumTopics: Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
• 513. Find Bottom Left Tree Value - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3460. Count the Number of Inversions - HardTopics: Array, Dynamic Programming
• 591. Tag Validator - HardTopics: String, Stack
• 3062. Create a DataFrame from List - EasyTopics:
• 3790. Fruits Into Baskets II - EasyTopics: Array, Binary Search, Segment Tree, Simulation, Ordered Set
• 2383. Add Two Integers - EasyTopics: Math
• 218. The Skyline Problem - HardTopics: Array, Divide and Conquer, Binary Indexed Tree, Segment Tree, Line Sweep, Heap (Priority Queue), Ordered Set
• 971. Shortest Bridge - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 928. Surface Area of 3D Shapes - EasyTopics: Array, Math, Geometry, Matrix
• 797. Rabbits in Forest - MediumTopics: Array, Hash Table, Math, Greedy
• 764. N-ary Tree Level Order Traversal - MediumTopics: Tree, Breadth-First Search
• 1197. Parsing A Boolean Expression - HardTopics: String, Stack, Recursion
• 1380. Number of Closed Islands - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 1460. Number of Substrings Containing All Three Characters - MediumTopics: Hash Table, String, Sliding Window
• 1561. Rearrange Words in a Sentence - MediumTopics: String, Sorting
• 2600. Maximum Tastiness of Candy Basket - MediumTopics: Array, Binary Search, Greedy, Sorting
• 2001. Jump Game VII - MediumTopics: String, Dynamic Programming, Sliding Window, Prefix Sum
• 1544. Count Good Nodes in Binary Tree - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2871. Double a Number Represented as a Linked List - MediumTopics: Linked List, Math, Stack
• 2038. Nearest Exit from Entrance in Maze - MediumTopics: Array, Breadth-First Search, Matrix
• 84. Largest Rectangle in Histogram - HardTopics: Array, Stack, Monotonic Stack
• 782. Jewels and Stones - EasyTopics: Hash Table, String
• 745. Find Smallest Letter Greater Than Target - EasyTopics: Array, Binary Search
• 3823. Count Islands With Total Value Divisible by K - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 3265. Maximum Good Subarray Sum - MediumTopics: Array, Hash Table, Prefix Sum
• 177. Nth Highest Salary - MediumTopics: Database
• 540. Single Element in a Sorted Array - MediumTopics: Array, Binary Search
• 1603. Running Sum of 1d Array - EasyTopics: Array, Prefix Sum
• 165. Compare Version Numbers - MediumTopics: Two Pointers, String
• 1035. Cousins in Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 698. Partition to K Equal Sum Subsets - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
• 714. Best Time to Buy and Sell Stock with Transaction Fee - MediumTopics: Array, Dynamic Programming, Greedy
• 221. Maximal Square - MediumTopics: Array, Dynamic Programming, Matrix
• 541. Reverse String II - EasyTopics: Two Pointers, String
• 1538. Maximum Points You Can Obtain from Cards - MediumTopics: Array, Sliding Window, Prefix Sum
• 2411. Spiral Matrix IV - MediumTopics: Array, Linked List, Matrix, Simulation
• 1039. Find the Town Judge - EasyTopics: Array, Hash Table, Graph
• 390. Elimination Game - MediumTopics: Math, Recursion
• 407. Trapping Rain Water II - HardTopics: Array, Breadth-First Search, Heap (Priority Queue), Matrix
• 2362. Minimum Rounds to Complete All Tasks - MediumTopics: Array, Hash Table, Greedy, Counting
• 1023. Time Based Key-Value Store - MediumTopics: Hash Table, String, Binary Search, Design
• 109. Convert Sorted List to Binary Search Tree - MediumTopics: Linked List, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
• 2732. Counter - EasyTopics:
• 815. Champagne Tower - MediumTopics: Dynamic Programming
• 921. Spiral Matrix III - MediumTopics: Array, Matrix, Simulation
• 695. Max Area of Island - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 464. Can I Win - MediumTopics: Math, Dynamic Programming, Bit Manipulation, Memoization, Game Theory, Bitmask
• 1025. Minimum Cost For Tickets - MediumTopics: Array, Dynamic Programming
• 2278. Find Three Consecutive Integers That Sum to a Given Number - MediumTopics: Math, Simulation
• 3329. Find the Length of the Longest Common Prefix - MediumTopics: Array, Hash Table, String, Trie
• 816. Design HashSet - EasyTopics: Array, Hash Table, Linked List, Design, Hash Function
• 2121. Find if Path Exists in Graph - EasyTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 1009. Pancake Sorting - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 2502. Sort the People - EasyTopics: Array, Hash Table, String, Sorting
• 196. Delete Duplicate Emails - EasyTopics: Database
• 638. Shopping Offers - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
• 35. Search Insert Position - EasyTopics: Array, Binary Search
• 833. Bus Routes - HardTopics: Array, Hash Table, Breadth-First Search
• 770. Couples Holding Hands - HardTopics: Greedy, Depth-First Search, Breadth-First Search, Union Find, Graph
• 2323. Minimum Bit Flips to Convert Number - EasyTopics: Bit Manipulation
• 1390. Average Selling Price - EasyTopics: Database
• 50. Pow(x, n) - MediumTopics: Math, Recursion
• 1459. Apply Discount Every n Orders - MediumTopics: Array, Hash Table, Design
• 768. Partition Labels - MediumTopics: Hash Table, Two Pointers, String, Greedy
• 1781. Check If Two String Arrays are Equivalent - EasyTopics: Array, String
• 742. To Lower Case - EasyTopics: String
• 1346. Maximize the Topmost Element After K Moves - MediumTopics: Array, Greedy
• 1478. Maximum Number of Events That Can Be Attended - MediumTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 1319. Unique Number of Occurrences - EasyTopics: Array, Hash Table
• 392. Is Subsequence - EasyTopics: Two Pointers, String, Dynamic Programming
• 800. Letter Case Permutation - MediumTopics: String, Backtracking, Bit Manipulation
• 324. Wiggle Sort II - MediumTopics: Array, Divide and Conquer, Greedy, Sorting, Quickselect
• 873. Guess the Word - HardTopics: Array, Math, String, Interactive, Game Theory
• 1605. Minimum Number of Days to Make m Bouquets - MediumTopics: Array, Binary Search
• 874. Backspace String Compare - EasyTopics: Two Pointers, String, Stack, Simulation
• 405. Convert a Number to Hexadecimal - EasyTopics: Math, String, Bit Manipulation
• 789. Kth Largest Element in a Stream - EasyTopics: Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream
• 240. Search a 2D Matrix II - MediumTopics: Array, Binary Search, Divide and Conquer, Matrix
• 547. Number of Provinces - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 2161. Stock Price Fluctuation - MediumTopics: Hash Table, Design, Heap (Priority Queue), Data Stream, Ordered Set
• 3376. Longest Common Suffix Queries - HardTopics: Array, String, Trie
• 1798. Max Number of K-Sum Pairs - MediumTopics: Array, Hash Table, Two Pointers, Sorting
• 877. Shortest Path Visiting All Nodes - HardTopics: Dynamic Programming, Bit Manipulation, Breadth-First Search, Graph, Bitmask
• 229. Majority Element II - MediumTopics: Array, Hash Table, Sorting, Counting
• 581. Shortest Unsorted Continuous Subarray - MediumTopics: Array, Two Pointers, Stack, Greedy, Sorting, Monotonic Stack
• 3231. Minimum Number of Coins to be Added - MediumTopics: Array, Greedy, Sorting
• 2186. Count Vowel Substrings of a String - EasyTopics: Hash Table, String
• 2144. Maximum Difference Between Increasing Elements - EasyTopics: Array
• 592. Fraction Addition and Subtraction - MediumTopics: Math, String, Simulation
• 1170. Shortest Common Supersequence - HardTopics: String, Dynamic Programming
• 1184. Car Pooling - MediumTopics: Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum
• 130. Surrounded Regions - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 95. Unique Binary Search Trees II - MediumTopics: Dynamic Programming, Backtracking, Tree, Binary Search Tree, Binary Tree
• 1353. Find Resultant Array After Removing Anagrams - EasyTopics: Array, Hash Table, String, Sorting
• 1402. Count Square Submatrices with All Ones - MediumTopics: Array, Dynamic Programming, Matrix
• 2605. Count Anagrams - HardTopics: Hash Table, Math, String, Combinatorics, Counting
• 1584. Average Salary Excluding the Minimum and Maximum Salary - EasyTopics: Array, Sorting
• 389. Find the Difference - EasyTopics: Hash Table, String, Bit Manipulation, Sorting
• 40. Combination Sum II - MediumTopics: Array, Backtracking
• 219. Contains Duplicate II - EasyTopics: Array, Hash Table, Sliding Window
• 321. Create Maximum Number - HardTopics: Array, Two Pointers, Stack, Greedy, Monotonic Stack
• 682. Baseball Game - EasyTopics: Array, Stack, Simulation
• 966. Binary Subarrays With Sum - MediumTopics: Array, Hash Table, Sliding Window, Prefix Sum
• 661. Image Smoother - EasyTopics: Array, Matrix
• 274. H-Index - MediumTopics: Array, Sorting, Counting Sort
• 554. Brick Wall - MediumTopics: Array, Hash Table
• 421. Maximum XOR of Two Numbers in an Array - MediumTopics: Array, Hash Table, Bit Manipulation, Trie
• 859. Design Circular Deque - MediumTopics: Array, Linked List, Design, Queue
• 373. Find K Pairs with Smallest Sums - MediumTopics: Array, Heap (Priority Queue)
• 583. Delete Operation for Two Strings - MediumTopics: String, Dynamic Programming
• 504. Base 7 - EasyTopics: Math, String
• 1293. Three Consecutive Odds - EasyTopics: Array
• 1055. Pairs of Songs With Total Durations Divisible by 60 - MediumTopics: Array, Hash Table, Counting
• 2050. Count Good Numbers - MediumTopics: Math, Recursion
• 3684. Substring Matching Pattern - EasyTopics: String, String Matching
• 2202. Sum of k-Mirror Numbers - HardTopics: Math, Enumeration
• 2743. Debounce - MediumTopics:
• 1397. Search Suggestions System - MediumTopics: Array, String, Binary Search, Trie, Sorting, Heap (Priority Queue)
• 1236. N-th Tribonacci Number - EasyTopics: Math, Dynamic Programming, Memoization
• 2032. Largest Odd Number in String - EasyTopics: Math, String, Greedy
• 1021. Distribute Coins in Binary Tree - MediumTopics: Tree, Depth-First Search, Binary Tree
• 2558. Minimum Number of Operations to Sort a Binary Tree by Level - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 1317. Monthly Transactions I - MediumTopics: Database
• 419. Battleships in a Board - MediumTopics: Array, Depth-First Search, Matrix
• 1130. Last Stone Weight II - MediumTopics: Array, Dynamic Programming
• 766. Flatten a Multilevel Doubly Linked List - MediumTopics: Linked List, Depth-First Search, Doubly-Linked List
• 2391. Strong Password Checker II - EasyTopics: String
• 1105. Uncrossed Lines - MediumTopics: Array, Dynamic Programming
• 2113. Find the Kth Largest Integer in the Array - MediumTopics: Array, String, Divide and Conquer, Sorting, Heap (Priority Queue), Quickselect
• 2428. Equal Row and Column Pairs - MediumTopics: Array, Hash Table, Matrix, Simulation
• 2608. Count the Digits That Divide a Number - EasyTopics: Math
• 367. Valid Perfect Square - EasyTopics: Math, Binary Search
• 1448. Maximum 69 Number - EasyTopics: Math, Greedy
• 1582. Design Browser History - MediumTopics: Array, Linked List, Stack, Design, Doubly-Linked List, Data Stream
• 870. Magic Squares In Grid - MediumTopics: Array, Hash Table, Math, Matrix
• 2591. Frog Jump II - MediumTopics: Array, Binary Search, Greedy
• 1586. Longest Subarray of 1's After Deleting One Element - MediumTopics: Array, Dynamic Programming, Sliding Window
• 203. Remove Linked List Elements - EasyTopics: Linked List, Recursion
• 1567. Maximum Number of Vowels in a Substring of Given Length - MediumTopics: String, Sliding Window
• 1146. Greatest Common Divisor of Strings - EasyTopics: Math, String
• 391. Perfect Rectangle - HardTopics: Array, Hash Table, Math, Geometry, Line Sweep
• 1078. Remove Outermost Parentheses - EasyTopics: String, Stack
• 608. Tree Node - MediumTopics: Database
• 1444. Number of Steps to Reduce a Number to Zero - EasyTopics: Math, Bit Manipulation
• 52. N-Queens II - HardTopics: Backtracking
• 1320. Remove All Adjacent Duplicates in String II - MediumTopics: String, Stack
• 1203. Print in Order - EasyTopics: Concurrency
• 1400. Find Winner on a Tic Tac Toe Game - EasyTopics: Array, Hash Table, Matrix, Simulation
• 655. Print Binary Tree - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2235. Capitalize the Title - EasyTopics: String
• 1050. Construct Binary Search Tree from Preorder Traversal - MediumTopics: Array, Stack, Tree, Binary Search Tree, Monotonic Stack, Binary Tree
• 1663. Detect Cycles in 2D Grid - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 1033. Broken Calculator - MediumTopics: Math, Greedy
• 739. Daily Temperatures - MediumTopics: Array, Stack, Monotonic Stack
• 1206. Corporate Flight Bookings - MediumTopics: Array, Prefix Sum
• 214. Shortest Palindrome - HardTopics: String, Rolling Hash, String Matching, Hash Function
• 2798. Chunk Array - EasyTopics:
• 755. Reach a Number - MediumTopics: Math, Binary Search
• 415. Add Strings - EasyTopics: Math, String, Simulation
• 551. Student Attendance Record I - EasyTopics: String
• 1310. Watering Plants - MediumTopics: Array, Simulation
• 969. Number of Recent Calls - EasyTopics: Design, Queue, Data Stream
• 2204. Find Subsequence of Length K With the Largest Sum - EasyTopics: Array, Hash Table, Sorting, Heap (Priority Queue)
• 595. Big Countries - EasyTopics: Database
• 1188. Brace Expansion II - HardTopics: String, Backtracking, Stack, Breadth-First Search
• 813. All Paths From Source to Target - MediumTopics: Backtracking, Depth-First Search, Breadth-First Search, Graph
• 58. Length of Last Word - EasyTopics: String
• 365. Water and Jug Problem - MediumTopics: Math, Depth-First Search, Breadth-First Search
• 2567. Closest Nodes Queries in a Binary Search Tree - MediumTopics: Array, Binary Search, Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 1129. Longest String Chain - MediumTopics: Array, Hash Table, Two Pointers, String, Dynamic Programming, Sorting
• 38. Count and Say - MediumTopics: String
• 1340. The Dining Philosophers - MediumTopics: Concurrency
• 1079. Sum of Root To Leaf Binary Numbers - EasyTopics: Tree, Depth-First Search, Binary Tree
• 697. Degree of an Array - EasyTopics: Array, Hash Table
• 953. Reverse Only Letters - EasyTopics: Two Pointers, String
• 1508. Longest Happy Prefix - HardTopics: String, Rolling Hash, String Matching, Hash Function
• 474. Ones and Zeroes - MediumTopics: Array, String, Dynamic Programming
• 931. Maximum Frequency Stack - HardTopics: Hash Table, Stack, Design, Ordered Set
• 2357. Count Integers in Intervals - HardTopics: Design, Segment Tree, Ordered Set
• 337. House Robber III - MediumTopics: Dynamic Programming, Tree, Depth-First Search, Binary Tree
• 2721. Sum of Distances - MediumTopics: Array, Hash Table, Prefix Sum
• 90. Subsets II - MediumTopics: Array, Backtracking, Bit Manipulation
• 191. Number of 1 Bits - EasyTopics: Divide and Conquer, Bit Manipulation
• 2248. Minimum Cost of Buying Candies With Discount - EasyTopics: Array, Greedy, Sorting
• 1022. Unique Paths III - HardTopics: Array, Backtracking, Bit Manipulation, Matrix
• 2216. Delete the Middle Node of a Linked List - MediumTopics: Linked List, Two Pointers
• 168. Excel Sheet Column Title - EasyTopics: Math, String
• 2352. Design an ATM Machine - MediumTopics: Array, Greedy, Design
• 628. Maximum Product of Three Numbers - EasyTopics: Array, Math, Sorting
• 2364. Longest Path With Different Adjacent Characters - HardTopics: Array, String, Tree, Depth-First Search, Graph, Topological Sort
• 746. Prefix and Suffix Search - HardTopics: Array, Hash Table, String, Design, Trie
• 2316. Count Hills and Valleys in an Array - EasyTopics: Array
• 624. Maximum Distance in Arrays - MediumTopics: Array, Greedy
• 3221. Find the Peaks - EasyTopics: Array, Enumeration
• 1392. Find the Difference of Two Arrays - EasyTopics: Array, Hash Table
• 1304. Longest Happy String - MediumTopics: String, Greedy, Heap (Priority Queue)
• 2169. Simple Bank System - MediumTopics: Array, Hash Table, Design, Simulation
• 3114. Beautiful Towers I - MediumTopics: Array, Stack, Monotonic Stack
• 115. Distinct Subsequences - HardTopics: String, Dynamic Programming
• 2793. Count the Number of Complete Components - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 1825. Find Minimum Time to Finish All Jobs - HardTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 2439. Longest Cycle in a Graph - HardTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 149. Max Points on a Line - HardTopics: Array, Hash Table, Math, Geometry
• 414. Third Maximum Number - EasyTopics: Array, Sorting
• 352. Data Stream as Disjoint Intervals - HardTopics: Binary Search, Design, Ordered Set
• 691. Stickers to Spell Word - HardTopics: Array, Hash Table, String, Dynamic Programming, Backtracking, Bit Manipulation, Memoization, Bitmask
• 338. Counting Bits - EasyTopics: Dynamic Programming, Bit Manipulation
• 520. Detect Capital - EasyTopics: String
• 1300. Critical Connections in a Network - HardTopics: Depth-First Search, Graph, Biconnected Component
• 480. Sliding Window Median - HardTopics: Array, Hash Table, Sliding Window, Heap (Priority Queue)
• 1408. Find the Smallest Divisor Given a Threshold - MediumTopics: Array, Binary Search
• 1016. Subarray Sums Divisible by K - MediumTopics: Array, Hash Table, Prefix Sum
• 1458. Sort Integers by The Number of 1 Bits - EasyTopics: Array, Bit Manipulation, Sorting, Counting
• 1492. Time Needed to Inform All Employees - MediumTopics: Tree, Depth-First Search, Breadth-First Search
• 1367. Maximum Height by Stacking Cuboids - HardTopics: Array, Dynamic Programming, Sorting
• 882. Peak Index in a Mountain Array - MediumTopics: Array, Binary Search
• 1058. Lexicographically Smallest Equivalent String - MediumTopics: String, Union Find
• 968. Beautiful Array - MediumTopics: Array, Math, Divide and Conquer
• 135. Candy - HardTopics: Array, Greedy
• 2250. K Highest Ranked Items Within a Price Range - MediumTopics: Array, Breadth-First Search, Sorting, Heap (Priority Queue), Matrix
• 1970. Sorting the Sentence - EasyTopics: String, Sorting
• 273. Integer to English Words - HardTopics: Math, String, Recursion
• 2488. Divide Intervals Into Minimum Number of Groups - MediumTopics: Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
• 332. Reconstruct Itinerary - HardTopics: Depth-First Search, Graph, Eulerian Circuit
• 1371. Minimum Remove to Make Valid Parentheses - MediumTopics: String, Stack
• 866. Rectangle Overlap - EasyTopics: Math, Geometry
• 2206. Detonate the Maximum Bombs - MediumTopics: Array, Math, Depth-First Search, Breadth-First Search, Graph, Geometry
• 602. Friend Requests II: Who Has the Most Friends - MediumTopics: Database
• 1877. Find Followers Count - EasyTopics: Database
• 1240. Stone Game II - MediumTopics: Array, Math, Dynamic Programming, Prefix Sum, Game Theory
• 185. Department Top Three Salaries - HardTopics: Database
• 781. Basic Calculator IV - HardTopics: Hash Table, Math, String, Stack, Recursion
• 3743. Reschedule Meetings for Maximum Free Time I - MediumTopics: Array, Greedy, Sliding Window
• 197. Rising Temperature - EasyTopics: Database
• 535. Encode and Decode TinyURL - MediumTopics: Hash Table, String, Design, Hash Function
• 1886. Minimum Limit of Balls in a Bag - MediumTopics: Array, Binary Search
• 967. Minimum Falling Path Sum - MediumTopics: Array, Dynamic Programming, Matrix
• 1541. Top Travellers - EasyTopics: Database
• 3627. Find Minimum Time to Reach Last Room I - MediumTopics: Array, Graph, Heap (Priority Queue), Matrix, Shortest Path
• 3194. Find Words Containing Character - EasyTopics: Array, String
• 1724. Customer Who Visited but Did Not Make Any Transactions - EasyTopics: Database
• 1753. Path With Minimum Effort - MediumTopics: Array, Binary Search, Depth-First Search, Breadth-First Search, Union Find, Heap (Priority Queue), Matrix
• 3197. Maximum Strong Pair XOR II - HardTopics: Array, Hash Table, Bit Manipulation, Trie, Sliding Window
• 1238. Alphabet Board Path - MediumTopics: Hash Table, String
• 1117. As Far from Land as Possible - MediumTopics: Array, Dynamic Programming, Breadth-First Search, Matrix
• 112. Path Sum - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 220. Contains Duplicate III - HardTopics: Array, Sliding Window, Sorting, Bucket Sort, Ordered Set
• 310. Minimum Height Trees - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 842. Card Flipping Game - MediumTopics: Array, Hash Table
• 690. Employee Importance - MediumTopics: Array, Hash Table, Tree, Depth-First Search, Breadth-First Search
• 2762. Cache With Time Limit - MediumTopics:
• 988. Flip Equivalent Binary Trees - MediumTopics: Tree, Depth-First Search, Binary Tree
• 2690. House Robber IV - MediumTopics: Array, Binary Search, Dynamic Programming, Greedy
• 639. Decode Ways II - HardTopics: String, Dynamic Programming
• 2015. Determine Whether Matrix Can Be Obtained By Rotation - EasyTopics: Array, Matrix
• 178. Rank Scores - MediumTopics: Database
• 722. Remove Comments - MediumTopics: Array, String
• 957. Minimum Add to Make Parentheses Valid - MediumTopics: String, Stack, Greedy
• 498. Diagonal Traverse - MediumTopics: Array, Matrix, Simulation
• 976. Minimum Area Rectangle - MediumTopics: Array, Hash Table, Math, Geometry, Sorting
• 1275. Validate Binary Tree Nodes - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Union Find, Graph, Binary Tree
• 662. Maximum Width of Binary Tree - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3639. Zero Array Transformation I - MediumTopics: Array, Prefix Sum
• 3437. Maximum Total Damage With Spell Casting - MediumTopics: Array, Hash Table, Two Pointers, Binary Search, Dynamic Programming, Sorting, Counting
• 1241. Decompress Run-Length Encoded List - EasyTopics: Array
• 1446. Angle Between Hands of a Clock - MediumTopics: Math
• 686. Repeated String Match - MediumTopics: String, String Matching
• 24. Swap Nodes in Pairs - MediumTopics: Linked List, Recursion
• 2024. Calculate Special Bonus - EasyTopics: Database
• 2627. Difference Between Maximum and Minimum Price Sum - HardTopics: Array, Dynamic Programming, Tree, Depth-First Search
• 1461. Count All Valid Pickup and Delivery Options - HardTopics: Math, Dynamic Programming, Combinatorics
• 674. Longest Continuous Increasing Subsequence - EasyTopics: Array
• 1706. Min Cost to Connect All Points - MediumTopics: Array, Union Find, Graph, Minimum Spanning Tree
• 87. Scramble String - HardTopics: String, Dynamic Programming
• 998. Check Completeness of a Binary Tree - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 2344. Escape the Spreading Fire - HardTopics: Array, Binary Search, Breadth-First Search, Matrix
• 3797. Design Spreadsheet - MediumTopics: Array, Hash Table, String, Design, Matrix
• 2210. Find Target Indices After Sorting Array - EasyTopics: Array, Binary Search, Sorting
• 906. Walking Robot Simulation - MediumTopics: Array, Hash Table, Simulation
• 375. Guess Number Higher or Lower II - MediumTopics: Math, Dynamic Programming, Game Theory
• 2662. Check Knight Tour Configuration - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
• 1415. Students and Examinations - EasyTopics: Database
• 2483. Task Scheduler II - MediumTopics: Array, Hash Table, Simulation
• 892. Shortest Subarray with Sum at Least K - HardTopics: Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
• 258. Add Digits - EasyTopics: Math, Simulation, Number Theory
• 3206. Find Common Elements Between Two Arrays - EasyTopics: Array, Hash Table
• 2433. Best Poker Hand - EasyTopics: Array, Hash Table, Counting
• 713. Subarray Product Less Than K - MediumTopics: Array, Binary Search, Sliding Window, Prefix Sum
• 526. Beautiful Arrangement - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 1803. Average Waiting Time - MediumTopics: Array, Simulation
• 3801. Count Beautiful Numbers - HardTopics: Dynamic Programming
• 452. Minimum Number of Arrows to Burst Balloons - MediumTopics: Array, Greedy, Sorting
• 2162. Partition Array Into Two Arrays to Minimize Sum Difference - HardTopics: Array, Two Pointers, Binary Search, Dynamic Programming, Bit Manipulation, Ordered Set, Bitmask
• 2165. Plates Between Candles - MediumTopics: Array, String, Binary Search, Prefix Sum
• 763. Special Binary String - HardTopics: String, Recursion
• 1547. Destination City - EasyTopics: Array, Hash Table, String
• 2725. Mice and Cheese - MediumTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 3113. Beautiful Towers II - MediumTopics: Array, Stack, Monotonic Stack
• 696. Count Binary Substrings - EasyTopics: Two Pointers, String
• 575. Distribute Candies - EasyTopics: Array, Hash Table
• 1505. Create Target Array in the Given Order - EasyTopics: Array, Simulation
• 319. Bulb Switcher - MediumTopics: Math, Brainteaser
• 449. Serialize and Deserialize BST - MediumTopics: String, Tree, Depth-First Search, Breadth-First Search, Design, Binary Search Tree, Binary Tree
• 3275. Minimum Number of Pushes to Type Word I - EasyTopics: Math, String, Greedy
• 795. K-th Symbol in Grammar - MediumTopics: Math, Bit Manipulation, Recursion
• 1254. Deepest Leaves Sum - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 1528. Kids With the Greatest Number of Candies - EasyTopics: Array
• 2475. Largest Palindromic Number - MediumTopics: Hash Table, String, Greedy, Counting
• 1139. Previous Permutation With One Swap - MediumTopics: Array, Greedy
• 3455. Minimum Length of String After Operations - MediumTopics: Hash Table, String, Counting
• 1616. Minimum Difference Between Largest and Smallest Value in Three Moves - MediumTopics: Array, Greedy, Sorting
• 463. Island Perimeter - EasyTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 2602. Maximum Enemy Forts That Can Be Captured - EasyTopics: Array, Two Pointers
• 2260. Divide a String Into Groups of Size k - EasyTopics: String, Simulation
• 1741. Sort Array by Increasing Frequency - EasyTopics: Array, Hash Table, Sorting
• 2022. Maximum Alternating Subsequence Sum - MediumTopics: Array, Dynamic Programming
• 2670. Make K-Subarray Sums Equal - MediumTopics: Array, Math, Greedy, Sorting, Number Theory
• 1777. Determine if Two Strings Are Close - MediumTopics: Hash Table, String, Sorting, Counting
• 864. Image Overlap - MediumTopics: Array, Matrix
• 1155. Product Sales Analysis III - MediumTopics: Database
• 987. Reveal Cards In Increasing Order - MediumTopics: Array, Queue, Sorting, Simulation
• 1031. Add to Array-Form of Integer - EasyTopics: Array, Math
• 2461. Amount of Time for Binary Tree to Be Infected - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2449. Maximum Number of Robots Within Budget - HardTopics: Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue
• 1656. Count Good Triplets - EasyTopics: Array, Enumeration
• 506. Relative Ranks - EasyTopics: Array, Sorting, Heap (Priority Queue)
• 166. Fraction to Recurring Decimal - MediumTopics: Hash Table, Math, String
• 1776. Minimum Operations to Reduce X to Zero - MediumTopics: Array, Hash Table, Binary Search, Sliding Window, Prefix Sum
• 556. Next Greater Element III - MediumTopics: Math, Two Pointers, String
• 2882. Ways to Express an Integer as Sum of Powers - MediumTopics: Dynamic Programming
• 963. Three Equal Parts - HardTopics: Array, Math
• 1379. Reconstruct a 2-Row Binary Matrix - MediumTopics: Array, Greedy, Matrix
• 1902. Car Fleet II - HardTopics: Array, Math, Stack, Heap (Priority Queue), Monotonic Stack
• 448. Find All Numbers Disappeared in an Array - EasyTopics: Array, Hash Table
• 2279. Maximum Split of Positive Even Integers - MediumTopics: Math, Backtracking, Greedy
• 552. Student Attendance Record II - HardTopics: Dynamic Programming
• 2671. Shortest Cycle in a Graph - HardTopics: Breadth-First Search, Graph
• 1032. Satisfiability of Equality Equations - MediumTopics: Array, String, Union Find, Graph
• 1114. Binary Search Tree to Greater Sum Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 1534. Minimum Number of Frogs Croaking - MediumTopics: String, Counting
• 2078. Maximum Compatibility Score Sum - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 972. Knight Dialer - MediumTopics: Dynamic Programming
• 1651. Shuffle String - EasyTopics: Array, String
• 648. Replace Words - MediumTopics: Array, Hash Table, String, Trie
• 2679. Count Distinct Numbers on Board - EasyTopics: Array, Hash Table, Math, Simulation
• 1034. Subarrays with K Different Integers - HardTopics: Array, Hash Table, Sliding Window, Counting
• 1848. Sum of Unique Elements - EasyTopics: Array, Hash Table, Counting
• 2734. Array Prototype Last - EasyTopics:
• 1993. Sum of All Subset XOR Totals - EasyTopics: Array, Math, Backtracking, Bit Manipulation, Combinatorics, Enumeration
• 2109. Find Array Given Subset Sums - HardTopics: Array, Divide and Conquer
• 2609. Distinct Prime Factors of Product of Array - MediumTopics: Array, Hash Table, Math, Number Theory
• 1734. Bank Account Summary II - EasyTopics: Database
• 685. Redundant Connection II - HardTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 257. Binary Tree Paths - EasyTopics: String, Backtracking, Tree, Depth-First Search, Binary Tree
• 486. Predict the Winner - MediumTopics: Array, Math, Dynamic Programming, Recursion, Game Theory
• 1549. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit - MediumTopics: Array, Queue, Sliding Window, Heap (Priority Queue), Ordered Set, Monotonic Queue
• 2556. Convert the Temperature - EasyTopics: Math
• 3104. Happy Students - MediumTopics: Array, Sorting, Enumeration
• 1765. Merge In Between Linked Lists - MediumTopics: Linked List
• 2480. Find Subarrays With Equal Sum - EasyTopics: Array, Hash Table
• 233. Number of Digit One - HardTopics: Math, Dynamic Programming, Recursion
• 2254. Check if Every Row and Column Contains All Numbers - EasyTopics: Array, Hash Table, Matrix
• 749. Shortest Completing Word - EasyTopics: Array, Hash Table, String
• 1929. Maximum Value at a Given Index in a Bounded Array - MediumTopics: Math, Binary Search, Greedy
• 2227. Sum of Subarray Ranges - MediumTopics: Array, Stack, Monotonic Stack
• 2819. Remove Trailing Zeros From a String - EasyTopics: String
• 2392. Successful Pairs of Spells and Potions - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 1916. Find Center of Star Graph - EasyTopics: Graph
• 3428. Find the XOR of Numbers Which Appear Twice - EasyTopics: Array, Hash Table, Bit Manipulation
• 3227. Find Missing and Repeated Values - EasyTopics: Array, Hash Table, Math, Matrix
• 1642. Water Bottles - EasyTopics: Math, Simulation
• 812. Rotate String - EasyTopics: String, String Matching
• 357. Count Numbers with Unique Digits - MediumTopics: Math, Dynamic Programming, Backtracking
• 303. Range Sum Query - Immutable - EasyTopics: Array, Design, Prefix Sum
• 1360. Maximum Length of a Concatenated String with Unique Characters - MediumTopics: Array, String, Backtracking, Bit Manipulation
• 2119. Minimum Number of Operations to Make Array Continuous - HardTopics: Array, Hash Table, Binary Search, Sliding Window
• 192. Word Frequency - MediumTopics: Shell
• 2654. Count the Number of Vowel Strings in Range - EasyTopics: Array, String, Counting
• 447. Number of Boomerangs - MediumTopics: Array, Hash Table, Math
• 2221. Check if a Parentheses String Can Be Valid - MediumTopics: String, Stack, Greedy
• 1284. Four Divisors - MediumTopics: Array, Math
• 949. Cat and Mouse - HardTopics: Math, Dynamic Programming, Graph, Topological Sort, Memoization, Game Theory
• 3242. Count Elements With Maximum Frequency - EasyTopics: Array, Hash Table, Counting
• 1637. String Compression II - HardTopics: String, Dynamic Programming
• 934. Bitwise ORs of Subarrays - MediumTopics: Array, Dynamic Programming, Bit Manipulation
• 1859. Change Minimum Characters to Satisfy One of Three Conditions - MediumTopics: Hash Table, String, Counting, Prefix Sum
• 665. Non-decreasing Array - MediumTopics: Array
• 1580. Shuffle the Array - EasyTopics: Array
• 1493. Frog Position After T Seconds - HardTopics: Tree, Depth-First Search, Breadth-First Search, Graph
• 3903. Inverse Coin Change - MediumTopics: Array, Dynamic Programming
• 1817. Calculate Money in Leetcode Bank - EasyTopics: Math
• 1043. Grid Illumination - HardTopics: Array, Hash Table
• 611. Valid Triangle Number - MediumTopics: Array, Two Pointers, Binary Search, Greedy, Sorting
• 878. Shifting Letters - MediumTopics: Array, String, Prefix Sum
• 620. Not Boring Movies - EasyTopics: Database
• 3371. Harshad Number - EasyTopics: Math
• 3435. Block Placement Queries - HardTopics: Array, Binary Search, Binary Indexed Tree, Segment Tree
• 117. Populating Next Right Pointers in Each Node II - MediumTopics: Linked List, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 670. Maximum Swap - MediumTopics: Math, Greedy
• 688. Knight Probability in Chessboard - MediumTopics: Dynamic Programming
• 1755. Defuse the Bomb - EasyTopics: Array, Sliding Window
• 2864. Is Object Empty - EasyTopics:
• 1861. Building Boxes - HardTopics: Math, Binary Search, Greedy
• 1957. Closest Room - HardTopics: Array, Binary Search, Sorting, Ordered Set
• 1288. Maximum Subarray Sum with One Deletion - MediumTopics: Array, Dynamic Programming
• 2212. Removing Minimum and Maximum From Array - MediumTopics: Array, Greedy
• 977. Distinct Subsequences II - HardTopics: String, Dynamic Programming
• 404. Sum of Left Leaves - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 393. UTF-8 Validation - MediumTopics: Array, Bit Manipulation
• 862. Find And Replace in String - MediumTopics: Array, Hash Table, String, Sorting
• 2348. Count Number of Texts - MediumTopics: Hash Table, Math, String, Dynamic Programming
• 1786. Count the Number of Consistent Strings - EasyTopics: Array, Hash Table, String, Bit Manipulation, Counting
• 1995. Finding Pairs With a Certain Sum - MediumTopics: Array, Hash Table, Design
• 1054. Complement of Base 10 Integer - EasyTopics: Bit Manipulation
• 1482. How Many Numbers Are Smaller Than the Current Number - EasyTopics: Array, Hash Table, Sorting, Counting Sort
• 1890. Sum of Beauty of All Substrings - MediumTopics: Hash Table, String, Counting
• 1081. Video Stitching - MediumTopics: Array, Dynamic Programming, Greedy
• 1829. Maximum Units on a Truck - EasyTopics: Array, Greedy, Sorting
• 646. Maximum Length of Pair Chain - MediumTopics: Array, Dynamic Programming, Greedy, Sorting
• 740. Delete and Earn - MediumTopics: Array, Hash Table, Dynamic Programming
• 1278. Product Price at a Given Date - MediumTopics: Database
• 2170. Count Number of Maximum Bitwise-OR Subsets - MediumTopics: Array, Backtracking, Bit Manipulation, Enumeration
• 514. Freedom Trail - HardTopics: String, Dynamic Programming, Depth-First Search, Breadth-First Search
• 3792. Find Invalid IP Addresses - HardTopics: Database
• 1406. Subtract the Product and Sum of Digits of an Integer - EasyTopics: Math
• 181. Employees Earning More Than Their Managers - EasyTopics: Database
• 637. Average of Levels in Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 917. Boats to Save People - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 3426. Minimum Number of Chairs in a Waiting Room - EasyTopics: String, Simulation
• 1972. Rotating the Box - MediumTopics: Array, Two Pointers, Matrix
• 1305. Number of Visible People in a Queue - HardTopics: Array, Stack, Monotonic Stack
• 1737. Maximum Nesting Depth of the Parentheses - EasyTopics: String, Stack
• 184. Department Highest Salary - MediumTopics: Database
• 2138. Sum of Beauty in the Array - MediumTopics: Array
• 1920. Determine Color of a Chessboard Square - EasyTopics: Math, String
• 3848. Analyze Subscription Conversion - MediumTopics: Database
• 1437. Minimum Insertion Steps to Make a String Palindrome - HardTopics: String, Dynamic Programming
• 476. Number Complement - EasyTopics: Bit Manipulation
• 1370. Count Number of Nice Subarrays - MediumTopics: Array, Hash Table, Math, Sliding Window, Prefix Sum
• 459. Repeated Substring Pattern - EasyTopics: String, String Matching
• 2409. Number of Increasing Paths in a Grid - HardTopics: Array, Dynamic Programming, Depth-First Search, Breadth-First Search, Graph, Topological Sort, Memoization, Matrix
• 925. Construct Binary Tree from Preorder and Postorder Traversal - MediumTopics: Array, Hash Table, Divide and Conquer, Tree, Binary Tree
• 1253. Sort the Matrix Diagonally - MediumTopics: Array, Sorting, Matrix
• 2271. Rearrange Array Elements by Sign - MediumTopics: Array, Two Pointers, Simulation
• 473. Matchsticks to Square - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 1587. Parallel Courses II - HardTopics: Dynamic Programming, Bit Manipulation, Graph, Bitmask
• 2048. Build Array from Permutation - EasyTopics: Array, Simulation
• 3708. Zigzag Grid Traversal With Skip - EasyTopics: Array, Matrix, Simulation
• 260. Single Number III - MediumTopics: Array, Bit Manipulation
• 2312. Most Frequent Number Following Key In an Array - EasyTopics: Array, Hash Table, Counting
• 1622. Max Value of Equation - HardTopics: Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
• 30. Substring with Concatenation of All Words - HardTopics: Hash Table, String, Sliding Window
• 943. Sum of Subarray Minimums - MediumTopics: Array, Dynamic Programming, Stack, Monotonic Stack
• 1401. Number of Burgers with No Waste of Ingredients - MediumTopics: Math
• 811. Number of Subarrays with Bounded Maximum - MediumTopics: Array, Two Pointers
• 2733. Sleep - EasyTopics:
• 1316. Fizz Buzz Multithreaded - MediumTopics: Concurrency
• 1516. The k-th Lexicographical String of All Happy Strings of Length n - MediumTopics: String, Backtracking
• 1299. K-Concatenation Maximum Sum - MediumTopics: Array, Dynamic Programming
• 2486. Most Frequent Even Element - EasyTopics: Array, Hash Table, Counting
• 2057. Count Salary Categories - MediumTopics: Database
• 3325. Find the Largest Area of Square Inside Two Rectangles - MediumTopics: Array, Math, Geometry
• 2536. Determine if Two Events Have Conflict - EasyTopics: Array, String
• 2118. Maximum Earnings From Taxi - MediumTopics: Array, Hash Table, Binary Search, Dynamic Programming, Sorting
• 2757. Count of Integers - HardTopics: Math, String, Dynamic Programming
• 1174. Sales Analysis III - EasyTopics: Database
• 2345. Minimum Number of Operations to Convert Time - EasyTopics: String, Greedy
• 2061. Painting a Grid With Three Different Colors - HardTopics: Dynamic Programming
• 2171. Second Minimum Time to Reach Destination - HardTopics: Breadth-First Search, Graph, Shortest Path
• 3496. Minimum Number of Seconds to Make Mountain Height Zero - MediumTopics: Array, Math, Binary Search, Greedy, Heap (Priority Queue)
• 767. Prime Number of Set Bits in Binary Representation - EasyTopics: Math, Bit Manipulation
• 1900. Closest Dessert Cost - MediumTopics: Array, Dynamic Programming, Backtracking
• 2429. Design a Food Rating System - MediumTopics: Array, Hash Table, String, Design, Heap (Priority Queue), Ordered Set
• 3243. Count the Number of Powerful Integers - HardTopics: Math, String, Dynamic Programming
• 406. Queue Reconstruction by Height - MediumTopics: Array, Binary Indexed Tree, Segment Tree, Sorting
• 2761. Array Reduce Transformation - EasyTopics:
• 2812. Find the Maximum Achievable Number - EasyTopics: Math
• 3886. Count Number of Trapezoids I - MediumTopics: Array, Hash Table, Math, Geometry
• 2192. Minimum Cost Homecoming of a Robot in a Grid - MediumTopics: Array, Greedy
• 2559. Maximum Number of Non-overlapping Palindrome Substrings - HardTopics: Two Pointers, String, Dynamic Programming, Greedy
• 994. Prison Cells After N Days - MediumTopics: Array, Hash Table, Math, Bit Manipulation
• 836. Race Car - HardTopics: Dynamic Programming
• 3620. Maximum Number of Distinct Elements After Operations - MediumTopics: Array, Greedy, Sorting
• 481. Magical String - MediumTopics: Two Pointers, String
• 2049. Eliminate Maximum Number of Monsters - MediumTopics: Array, Greedy, Sorting
• 228. Summary Ranges - EasyTopics: Array
• 607. Sales Person - EasyTopics: Database
• 890. Lemonade Change - EasyTopics: Array, Greedy
• 941. Sort Array By Parity - EasyTopics: Array, Two Pointers, Sorting
• 645. Set Mismatch - EasyTopics: Array, Hash Table, Bit Manipulation, Sorting
• 57. Insert Interval - MediumTopics: Array
• 402. Remove K Digits - MediumTopics: String, Stack, Greedy, Monotonic Stack
• 386. Lexicographical Numbers - MediumTopics: Depth-First Search, Trie
• 667. Beautiful Arrangement II - MediumTopics: Array, Math
• 2317. Count Collisions on a Road - MediumTopics: String, Stack, Simulation
• 327. Count of Range Sum - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 3181. Find Building Where Alice and Bob Can Meet - HardTopics: Array, Binary Search, Stack, Binary Indexed Tree, Segment Tree, Heap (Priority Queue), Monotonic Stack
• 1358. Find Positive Integer Solution for a Given Equation - MediumTopics: Math, Two Pointers, Binary Search, Interactive
• 2756. Buy Two Chocolates - EasyTopics: Array, Greedy, Sorting
• 1160. Letter Tile Possibilities - MediumTopics: Hash Table, String, Backtracking, Counting
• 532. K-diff Pairs in an Array - MediumTopics: Array, Hash Table, Two Pointers, Binary Search, Sorting
• 3601. Find the K-th Character in String Game II - HardTopics: Math, Bit Manipulation, Recursion
• 776. N-ary Tree Postorder Traversal - EasyTopics: Stack, Tree, Depth-First Search
• 1833. Find the Highest Altitude - EasyTopics: Array, Prefix Sum
• 2870. Longest Alternating Subarray - EasyTopics: Array, Enumeration
• 466. Count The Repetitions - HardTopics: String, Dynamic Programming
• 566. Reshape the Matrix - EasyTopics: Array, Matrix, Simulation
• 2646. Kth Largest Sum in a Binary Tree - MediumTopics: Tree, Breadth-First Search, Sorting, Binary Tree
• 775. N-ary Tree Preorder Traversal - EasyTopics: Stack, Tree, Depth-First Search
• 2262. Solving Questions With Brainpower - MediumTopics: Array, Dynamic Programming
• 888. Mirror Reflection - MediumTopics: Math, Geometry, Number Theory
• 932. Monotonic Array - EasyTopics: Array
• 913. Random Flip Matrix - MediumTopics: Hash Table, Math, Reservoir Sampling, Randomized
• 3897. Count Number of Trapezoids II - HardTopics: Array, Hash Table, Math, Geometry
• 570. Managers with at Least 5 Direct Reports - MediumTopics: Database
• 3031. Construct Product Matrix - MediumTopics: Array, Matrix, Prefix Sum
• 2298. Count Integers With Even Digit Sum - EasyTopics: Math, Simulation
• 2031. Egg Drop With 2 Eggs and N Floors - MediumTopics: Math, Dynamic Programming
• 1984. Maximum Distance Between a Pair of Values - MediumTopics: Array, Two Pointers, Binary Search
• 262. Trips and Users - HardTopics: Database
• 587. Erect the Fence - HardTopics: Array, Math, Geometry
• 113. Path Sum II - MediumTopics: Backtracking, Tree, Depth-First Search, Binary Tree
• 2736. Minimum Additions to Make Valid String - MediumTopics: String, Dynamic Programming, Stack, Greedy
• 1092. Maximum Difference Between Node and Ancestor - MediumTopics: Tree, Depth-First Search, Binary Tree
• 3412. Permutation Difference between Two Strings - EasyTopics: Hash Table, String
• 1324. Where Will the Ball Fall - MediumTopics: Array, Matrix, Simulation
• 875. Longest Mountain in Array - MediumTopics: Array, Two Pointers, Dynamic Programming, Enumeration
• 3571. Length of the Longest Increasing Path - HardTopics: Array, Binary Search, Sorting
• 187. Repeated DNA Sequences - MediumTopics: Hash Table, String, Bit Manipulation, Sliding Window, Rolling Hash, Hash Function
• 1499. Maximum Performance of a Team - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 2686. Minimum Cost of a Path With Special Roads - MediumTopics: Array, Graph, Heap (Priority Queue), Shortest Path
• 524. Longest Word in Dictionary through Deleting - MediumTopics: Array, Two Pointers, String, Sorting
• 3152. Maximum Value of an Ordered Triplet II - MediumTopics: Array
• 1393. Maximum Value of K Coins From Piles - HardTopics: Array, Dynamic Programming, Prefix Sum
• 2777. Find the Distinct Difference Array - EasyTopics: Array, Hash Table
• 1757. Minimum Jumps to Reach Home - MediumTopics: Array, Dynamic Programming, Breadth-First Search
• 1628. Count Submatrices With All Ones - MediumTopics: Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
• 2137. Final Value of Variable After Performing Operations - EasyTopics: Array, String, Simulation
• 1946. Minimum Absolute Sum Difference - MediumTopics: Array, Binary Search, Sorting, Ordered Set
• 1851. Maximum Number of Events That Can Be Attended II - HardTopics: Array, Binary Search, Dynamic Programming, Sorting
• 3716. Longest Subsequence With Decreasing Adjacent Difference - MediumTopics: Array, Dynamic Programming
• 2207. Sequentially Ordinal Rank Tracker - HardTopics: Design, Heap (Priority Queue), Data Stream, Ordered Set
• 3653. Maximum Subarray Sum With Length Divisible by K - MediumTopics: Array, Hash Table, Prefix Sum
• 2067. Maximum Number of Points with Cost - MediumTopics: Array, Dynamic Programming, Matrix
• 1574. Maximum Product of Two Elements in an Array - EasyTopics: Array, Sorting, Heap (Priority Queue)
• 3423. Maximum Sum of Subsequence With Non-adjacent Elements - HardTopics: Array, Divide and Conquer, Dynamic Programming, Segment Tree
• 1677. Matrix Diagonal Sum - EasyTopics: Array, Matrix
• 871. Keys and Rooms - MediumTopics: Depth-First Search, Breadth-First Search, Graph
• 1876. Map of Highest Peak - MediumTopics: Array, Breadth-First Search, Matrix
• 2521. Paths in Matrix Whose Sum Is Divisible by K - HardTopics: Array, Dynamic Programming, Matrix
• 537. Complex Number Multiplication - MediumTopics: Math, String, Simulation
• 1871. Palindrome Partitioning IV - HardTopics: String, Dynamic Programming
• 3644. Minimum Positive Sum Subarray - EasyTopics: Array, Sliding Window, Prefix Sum
• 1583. Paint House III - HardTopics: Array, Dynamic Programming
• 676. Implement Magic Dictionary - MediumTopics: Hash Table, String, Depth-First Search, Design, Trie
• 492. Construct the Rectangle - EasyTopics: Math
• 1971. Incremental Memory Leak - MediumTopics: Math, Simulation
• 633. Sum of Square Numbers - MediumTopics: Math, Two Pointers, Binary Search
• 1720. Crawler Log Folder - EasyTopics: Array, String, Stack
• 488. Zuma Game - HardTopics: String, Dynamic Programming, Stack, Breadth-First Search, Memoization
• 1648. Minimum Insertions to Balance a Parentheses String - MediumTopics: String, Stack, Greedy
• 3093. Sum of Values at Indices With K Set Bits - EasyTopics: Array, Bit Manipulation
• 2397. Count Number of Ways to Place Houses - MediumTopics: Dynamic Programming
• 3324. Split the Array - EasyTopics: Array, Hash Table, Counting
• 2219. Maximum Number of Words Found in Sentences - EasyTopics: Array, String
• 2368. Sum of Total Strength of Wizards - HardTopics: Array, Stack, Monotonic Stack, Prefix Sum
• 657. Robot Return to Origin - EasyTopics: String, Simulation
• 2060. Merge BSTs to Create Single BST - HardTopics: Hash Table, Binary Search, Tree, Depth-First Search, Binary Tree
• 1018. Largest Perimeter Triangle - EasyTopics: Array, Math, Greedy, Sorting
• 671. Second Minimum Node In a Binary Tree - EasyTopics: Tree, Depth-First Search, Binary Tree
• 2245. Destroying Asteroids - MediumTopics: Array, Greedy, Sorting
• 2220. Find All Possible Recipes from Given Supplies - MediumTopics: Array, Hash Table, String, Graph, Topological Sort
• 2616. Maximal Score After Applying K Operations - MediumTopics: Array, Greedy, Heap (Priority Queue)
• 2715. K Items With the Maximum Sum - EasyTopics: Math, Greedy
• 1116. Maximum Level Sum of a Binary Tree - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 1711. Find Valid Matrix Given Row and Column Sums - MediumTopics: Array, Greedy, Matrix
• 1529. Max Difference You Can Get From Changing an Integer - MediumTopics: Math, Greedy
• 2328. Minimize Result by Adding Parentheses to Expression - MediumTopics: String, Enumeration
• 2147. The Score of Students Solving Math Expression - HardTopics: Array, Hash Table, Math, String, Dynamic Programming, Stack, Memoization
• 1005. Univalued Binary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3770. Lexicographically Smallest Generated String - HardTopics: String, Greedy, String Matching
• 3795. Zero Array Transformation IV - MediumTopics: Array, Dynamic Programming
• 1469. Minimum Number of Steps to Make Two Strings Anagram - MediumTopics: Hash Table, String, Counting
• 1872. Can You Eat Your Favorite Candy on Your Favorite Day? - MediumTopics: Array, Prefix Sum
• 1985. Maximum Subarray Min-Product - MediumTopics: Array, Stack, Monotonic Stack, Prefix Sum
• 584. Find Customer Referee - EasyTopics: Database
• 910. Nth Magical Number - HardTopics: Math, Binary Search
• 1258. Article Views I - EasyTopics: Database
• 1962. Single-Threaded CPU - MediumTopics: Array, Sorting, Heap (Priority Queue)
• 810. Valid Tic-Tac-Toe State - MediumTopics: Array, Matrix
• 1095. Two City Scheduling - MediumTopics: Array, Greedy, Sorting
• 2123. The Number of Weak Characters in the Game - MediumTopics: Array, Stack, Greedy, Sorting, Monotonic Stack
• 2151. The Time When the Network Becomes Idle - MediumTopics: Array, Breadth-First Search, Graph
• 307. Range Sum Query - Mutable - MediumTopics: Array, Divide and Conquer, Design, Binary Indexed Tree, Segment Tree
• 1522. Stone Game III - HardTopics: Array, Math, Dynamic Programming, Game Theory
• 2636. Maximum Subsequence Score - MediumTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 502. IPO - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 930. All Possible Full Binary Trees - MediumTopics: Dynamic Programming, Tree, Recursion, Memoization, Binary Tree
• 3784. Longest Common Prefix of K Strings After Removal - HardTopics: Array, String, Trie
• 1027. Sum of Even Numbers After Queries - MediumTopics: Array, Simulation
• 732. My Calendar III - HardTopics: Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set
• 1224. Minimum Falling Path Sum II - HardTopics: Array, Dynamic Programming, Matrix
• 1430. Find the K-Beauty of a Number - EasyTopics: Math, String, Sliding Window
• 891. Score After Flipping Matrix - MediumTopics: Array, Greedy, Bit Manipulation, Matrix
• 1866. Restore the Array From Adjacent Pairs - MediumTopics: Array, Hash Table, Depth-First Search
• 3019. Furthest Point From Origin - EasyTopics: String, Counting
• 216. Combination Sum III - MediumTopics: Array, Backtracking
• 619. Biggest Single Number - EasyTopics: Database
• 1349. Check If It Is a Straight Line - EasyTopics: Array, Math, Geometry
• 3919. Network Recovery Pathways - HardTopics: Array, Binary Search, Dynamic Programming, Graph, Topological Sort, Heap (Priority Queue), Shortest Path
• 306. Additive Number - MediumTopics: String, Backtracking
• 3741. Reschedule Meetings for Maximum Free Time II - MediumTopics: Array, Greedy, Enumeration
• 1888. Find Nearest Point That Has the Same X or Y Coordinate - EasyTopics: Array
• 1120. Flower Planting With No Adjacent - MediumTopics: Depth-First Search, Breadth-First Search, Graph
• 2319. Longest Substring of One Repeating Character - HardTopics: Array, String, Segment Tree, Ordered Set
• 1880. Largest Merge Of Two Strings - MediumTopics: Two Pointers, String, Greedy
• 3791. Fruits Into Baskets III - MediumTopics: Array, Binary Search, Segment Tree, Ordered Set
• 2103. Find All Groups of Farmland - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 1496. Lucky Numbers in a Matrix - EasyTopics: Array, Matrix
• 880. Rectangle Area II - HardTopics: Array, Segment Tree, Line Sweep, Ordered Set
• 493. Reverse Pairs - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 1555. Number of Ways of Cutting a Pizza - HardTopics: Array, Dynamic Programming, Memoization, Matrix, Prefix Sum
• 2648. Number of Ways to Earn Points - HardTopics: Array, Dynamic Programming
• 2606. Difference Between Ones and Zeros in Row and Column - MediumTopics: Array, Matrix, Simulation
• 916. Decoded String at Index - MediumTopics: String, Stack
• 1802. Number of Students Unable to Eat Lunch - EasyTopics: Array, Stack, Queue, Simulation
• 725. Split Linked List in Parts - MediumTopics: Linked List
• 1539. Diagonal Traverse II - MediumTopics: Array, Sorting, Heap (Priority Queue)
• 2283. Sort Even and Odd Indices Independently - EasyTopics: Array, Sorting
• 3446. Find the Number of Good Pairs I - EasyTopics: Array, Hash Table
• 2334. Number of Flowers in Full Bloom - HardTopics: Array, Hash Table, Binary Search, Sorting, Prefix Sum, Ordered Set
• 894. Random Pick with Blacklist - HardTopics: Array, Hash Table, Math, Binary Search, Sorting, Randomized
• 2306. Create Binary Tree From Descriptions - MediumTopics: Array, Hash Table, Tree, Binary Tree
• 1523. Capital Gain/Loss - MediumTopics: Database
• 951. Partition Array into Disjoint Intervals - MediumTopics: Array
• 2856. Count Complete Subarrays in an Array - MediumTopics: Array, Hash Table, Sliding Window
• 437. Path Sum III - MediumTopics: Tree, Depth-First Search, Binary Tree
• 2493. Reverse Odd Levels of Binary Tree - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 1631. Number of Sub-arrays With Odd Sum - MediumTopics: Array, Math, Dynamic Programming, Prefix Sum
• 1196. Filling Bookcase Shelves - MediumTopics: Array, Dynamic Programming
• 1342. Queens That Can Attack the King - MediumTopics: Array, Matrix, Simulation
• 354. Russian Doll Envelopes - HardTopics: Array, Binary Search, Dynamic Programming, Sorting
• 1826. Maximum XOR With an Element From Array - HardTopics: Array, Bit Manipulation, Trie
• 632. Smallest Range Covering Elements from K Lists - HardTopics: Array, Hash Table, Greedy, Sliding Window, Sorting, Heap (Priority Queue)
• 1849. Maximum Absolute Sum of Any Subarray - MediumTopics: Array, Dynamic Programming
• 2432. Number of Zero-Filled Subarrays - MediumTopics: Array, Math
• 2350. Find Closest Number to Zero - EasyTopics: Array
• 3854. Maximum Profit from Trading Stocks with Discounts - HardTopics: Array, Dynamic Programming, Tree, Depth-First Search
• 936. RLE Iterator - MediumTopics: Array, Design, Counting, Iterator
• 3451. String Compression III - MediumTopics: String
• 100. Same Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2088. Minimum Time to Type Word Using Special Typewriter - EasyTopics: String, Greedy
• 924. Fair Candy Swap - EasyTopics: Array, Hash Table, Binary Search, Sorting
• 964. Minimize Malware Spread II - HardTopics: Array, Hash Table, Depth-First Search, Breadth-First Search, Union Find, Graph
• 538. Convert BST to Greater Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 2472. Build a Matrix With Conditions - HardTopics: Array, Graph, Topological Sort, Matrix
• 1456. Find the City With the Smallest Number of Neighbors at a Threshold Distance - MediumTopics: Dynamic Programming, Graph, Shortest Path
• 2140. Longest Subsequence Repeated k Times - HardTopics: String, Backtracking, Greedy, Counting, Enumeration
• 2755. Extra Characters in a String - MediumTopics: Array, Hash Table, String, Dynamic Programming, Trie
• 1302. Delete Characters to Make Fancy String - EasyTopics: String
• 772. Construct Quad Tree - MediumTopics: Array, Divide and Conquer, Tree, Matrix
• 1878. Check if Array Is Sorted and Rotated - EasyTopics: Array
• 2665. Minimum Time to Repair Cars - MediumTopics: Array, Binary Search
• 718. Maximum Length of Repeated Subarray - MediumTopics: Array, Binary Search, Dynamic Programming, Sliding Window, Rolling Hash, Hash Function
• 1350. Remove Sub-Folders from the Filesystem - MediumTopics: Array, String, Depth-First Search, Trie
• 2039. Sum Game - MediumTopics: Math, String, Greedy, Game Theory
• 2156. Stone Game IX - MediumTopics: Array, Math, Greedy, Counting, Game Theory
• 1710. Find Servers That Handled Most Number of Requests - HardTopics: Array, Greedy, Heap (Priority Queue), Ordered Set
• 1813. Maximum Erasure Value - MediumTopics: Array, Hash Table, Sliding Window
• 2389. Design a Text Editor - HardTopics: Linked List, String, Stack, Design, Simulation, Doubly-Linked List
• 876. Hand of Straights - MediumTopics: Array, Hash Table, Greedy, Sorting
• 826. Soup Servings - MediumTopics: Math, Dynamic Programming, Probability and Statistics
• 2804. Compact Object - MediumTopics:
• 1442. Number of Operations to Make Network Connected - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 2386. Min Max Game - EasyTopics: Array, Simulation
• 2633. Minimum Cost to Split an Array - HardTopics: Array, Hash Table, Dynamic Programming, Counting
• 2145. Grid Game - MediumTopics: Array, Matrix, Prefix Sum
• 1951. Find the Winner of the Circular Game - MediumTopics: Array, Math, Recursion, Queue, Simulation
• 2044. Number of Wonderful Substrings - MediumTopics: Hash Table, String, Bit Manipulation, Prefix Sum
• 3486. Count the Number of Good Nodes - MediumTopics: Tree, Depth-First Search
• 2797. Event Emitter - MediumTopics:
• 2454. Largest Local Values in a Matrix - EasyTopics: Array, Matrix
• 983. Validate Stack Sequences - MediumTopics: Array, Stack, Simulation
• 3971. Find Stores with Inventory Imbalance - MediumTopics:
• 1471. Maximum Students Taking Exam - HardTopics: Array, Dynamic Programming, Bit Manipulation, Matrix, Bitmask
• 60. Permutation Sequence - HardTopics: Math, Recursion
• 806. Domino and Tromino Tiling - MediumTopics: Dynamic Programming
• 1121. Partition Array for Maximum Sum - MediumTopics: Array, Dynamic Programming
• 2058. Concatenation of Array - EasyTopics: Array, Simulation
• 1249. Snapshot Array - MediumTopics: Array, Hash Table, Binary Search, Design
• 1335. Maximum Candies Allocated to K Children - MediumTopics: Array, Binary Search
• 2876. Number of Employees Who Met the Target - EasyTopics: Array
• 3491. Find the Maximum Length of Valid Subsequence II - MediumTopics: Array, Dynamic Programming
• 1843. Number Of Rectangles That Can Form The Largest Square - EasyTopics: Array
• 3379. Score of a String - EasyTopics: String
• 1135. Customers Who Bought All Products - MediumTopics: Database
• 904. Leaf-Similar Trees - EasyTopics: Tree, Depth-First Search, Binary Tree
• 3948. Maximum Number of Subsequences After One Inserting - MediumTopics: String, Dynamic Programming, Greedy, Prefix Sum
• 2590. Maximum Star Sum of a Graph - MediumTopics: Array, Greedy, Graph, Sorting, Heap (Priority Queue)
• 1356. Minimum Number of Moves to Make Palindrome - HardTopics: Two Pointers, String, Greedy, Binary Indexed Tree
• 1063. Best Sightseeing Pair - MediumTopics: Array, Dynamic Programming
• 2128. Reverse Prefix of Word - EasyTopics: Two Pointers, String, Stack
• 1613. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree - HardTopics: Union Find, Graph, Sorting, Minimum Spanning Tree, Strongly Connected Component
• 1030. Smallest String Starting From Leaf - MediumTopics: String, Backtracking, Tree, Depth-First Search, Binary Tree
• 2664. Maximize Greatness of an Array - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 1064. Smallest Integer Divisible by K - MediumTopics: Hash Table, Math
• 829. Subdomain Visit Count - MediumTopics: Array, Hash Table, String, Counting
• 2748. Calculate Delayed Arrival Time - EasyTopics: Math
• 1556. Make Two Arrays Equal by Reversing Subarrays - EasyTopics: Array, Hash Table, Sorting
• 712. Minimum ASCII Delete Sum for Two Strings - MediumTopics: String, Dynamic Programming
• 2180. Maximum Number of Tasks You Can Assign - HardTopics: Array, Two Pointers, Binary Search, Greedy, Queue, Sorting, Monotonic Queue
• 1670. Patients With a Condition - EasyTopics: Database
• 2807. Execute Asynchronous Functions in Parallel - MediumTopics:
• 1771. Sell Diminishing-Valued Colored Balls - MediumTopics: Array, Math, Binary Search, Greedy, Sorting, Heap (Priority Queue)
• 1363. Greatest English Letter in Upper and Lower Case - EasyTopics: Hash Table, String, Enumeration
• 2632. Apply Bitwise Operations to Make Strings Equal - MediumTopics: String, Bit Manipulation
• 2707. Merge Two 2D Arrays by Summing Values - EasyTopics: Array, Hash Table, Two Pointers
• 2630. Alternating Digit Sum - EasyTopics: Math
• 1515. Find the Minimum Number of Fibonacci Numbers Whose Sum Is K - MediumTopics: Math, Greedy
• 2079. Delete Duplicate Folders in System - HardTopics: Array, Hash Table, String, Trie, Hash Function
• 3909. Minimum Increments to Equalize Leaf Paths - MediumTopics: Array, Dynamic Programming, Tree, Depth-First Search
• 2189. Maximum Path Quality of a Graph - HardTopics: Array, Backtracking, Graph
• 2783. Nested Array Generator - MediumTopics:
• 1552. Build an Array With Stack Operations - MediumTopics: Array, Stack, Simulation
• 879. Maximize Distance to Closest Person - MediumTopics: Array
• 1531. Number of Ways to Wear Different Hats to Each Other - HardTopics: Array, Dynamic Programming, Bit Manipulation, Bitmask
• 455. Assign Cookies - EasyTopics: Array, Two Pointers, Greedy, Sorting
• 3249. Minimum Number of Operations to Make Array XOR Equal to K - MediumTopics: Array, Bit Manipulation
• 1484. Linked List in Binary Tree - MediumTopics: Linked List, Tree, Depth-First Search, Binary Tree
• 3636. Check Balanced String - EasyTopics: String
• 1485. Minimum Cost to Make at Least One Valid Path in a Grid - HardTopics: Array, Breadth-First Search, Graph, Heap (Priority Queue), Matrix, Shortest Path
• 2703. Handling Sum Queries After Update - HardTopics: Array, Segment Tree
• 626. Exchange Seats - MediumTopics: Database
• 2766. Find the Prefix Common Array of Two Arrays - MediumTopics: Array, Hash Table, Bit Manipulation
• 596. Classes With at Least 5 Students - EasyTopics: Database
• 2087. Confirmation Rate - MediumTopics: Database
• 3941. Number of Integers With Popcount-Depth Equal to K II - HardTopics: Array, Divide and Conquer, Binary Indexed Tree, Segment Tree
• 1282. Number of Valid Words for Each Puzzle - HardTopics: Array, Hash Table, String, Bit Manipulation, Trie
• 3525. Maximum Energy Boost From Two Drinks - MediumTopics: Array, Dynamic Programming
• 3712. Minimum Cost to Make Arrays Identical - MediumTopics: Array, Greedy, Sorting
• 2789. Counter II - EasyTopics:
• 1830. Count Good Meals - MediumTopics: Array, Hash Table
• 1429. Verbal Arithmetic Puzzle - HardTopics: Array, Math, String, Backtracking
• 2117. Find Original Array From Doubled Array - MediumTopics: Array, Hash Table, Greedy, Sorting
• 2601. Number of Great Partitions - HardTopics: Array, Dynamic Programming
• 609. Find Duplicate File in System - MediumTopics: Array, Hash Table, String
• 2481. Strictly Palindromic Number - MediumTopics: Math, Two Pointers, Brainteaser
• 2090. Number of Ways to Arrive at Destination - MediumTopics: Dynamic Programming, Graph, Topological Sort, Shortest Path
• 1207. Delete Nodes And Return Forest - MediumTopics: Array, Hash Table, Tree, Depth-First Search, Binary Tree
• 2196. Reverse Nodes in Even Length Groups - MediumTopics: Linked List
• 3959. Maximum Total from Optimal Activation Order - MediumTopics: Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue)
• 1573. Find Two Non-overlapping Sub-arrays Each With Target Sum - MediumTopics: Array, Hash Table, Binary Search, Dynamic Programming, Sliding Window
• 1941. Minimum Number of Operations to Make String Sorted - HardTopics: Math, String, Combinatorics
• 1490. Generate a String With Characters That Have Odd Counts - EasyTopics: String
• 3649. Minimum Time to Break Locks I - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Depth-First Search, Bitmask
• 1457. Minimum Difficulty of a Job Schedule - HardTopics: Array, Dynamic Programming
• 3916. Minimum Time to Reach Destination in Directed Graph - MediumTopics: Graph, Heap (Priority Queue), Shortest Path
• 1042. Minimum Cost to Merge Stones - HardTopics: Array, Dynamic Programming, Prefix Sum
• 2267. Minimum Difference in Sums After Removal of Elements - HardTopics: Array, Dynamic Programming, Heap (Priority Queue)
• 3910. Find Books with No Available Copies - EasyTopics: Database
• 1424. Maximum Candies You Can Get from Boxes - HardTopics: Array, Breadth-First Search, Graph
• 2588. Maximum Number of Points From Grid Queries - HardTopics: Array, Two Pointers, Breadth-First Search, Union Find, Sorting, Heap (Priority Queue), Matrix
• 2531. Create Components With Same Value - HardTopics: Array, Math, Tree, Depth-First Search, Enumeration
• 3630. Total Characters in String After Transformations II - HardTopics: Hash Table, Math, String, Dynamic Programming, Counting
• 2572. Append Characters to String to Make Subsequence - MediumTopics: Two Pointers, String, Greedy
• 1678. Number of Ways to Split a String - MediumTopics: Math, String
• 2813. To Be Or Not To Be - EasyTopics:
• 2195. Time Needed to Buy Tickets - EasyTopics: Array, Queue, Simulation
• 3913. Partition Array to Minimize XOR - MediumTopics: Array, Dynamic Programming, Bit Manipulation, Prefix Sum
• 984. Most Stones Removed with Same Row or Column - MediumTopics: Hash Table, Depth-First Search, Union Find, Graph
• 1955. Seat Reservation Manager - MediumTopics: Design, Heap (Priority Queue)
• 3967. Earliest Finish Time for Land and Water Rides II - MediumTopics: Array, Two Pointers, Binary Search, Greedy, Sorting
• 201. Bitwise AND of Numbers Range - MediumTopics: Bit Manipulation
• 1744. Number of Ways to Form a Target String Given a Dictionary - HardTopics: Array, String, Dynamic Programming
• 1775. Design an Ordered Stream - EasyTopics: Array, Hash Table, Design, Data Stream
• 2231. Find First Palindromic String in the Array - EasyTopics: Array, Two Pointers, String
• 3344. Minimize Manhattan Distances - HardTopics: Array, Math, Geometry, Sorting, Ordered Set
• 1290. Make Array Strictly Increasing - HardTopics: Array, Binary Search, Dynamic Programming, Sorting
• 2867. Ways to Split Array Into Good Subarrays - MediumTopics: Array, Math, Dynamic Programming
• 586. Customer Placing the Largest Number of Orders - EasyTopics: Database
• 3396. Valid Word - EasyTopics: String
• 3944. Minimum Time to Activate String - MediumTopics: Array, Binary Search
• 445. Add Two Numbers II - MediumTopics: Linked List, Math, Stack
• 3531. Minimum Amount of Damage Dealt to Bob - HardTopics: Array, Greedy, Sorting
• 1791. Richest Customer Wealth - EasyTopics: Array, Matrix
• 601. Human Traffic of Stadium - HardTopics: Database
• 3349. Maximum Length Substring With Two Occurrences - EasyTopics: Hash Table, String, Sliding Window
• 1772. Create Sorted Array through Instructions - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 922. Possible Bipartition - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 3905. Partition String - MediumTopics: Hash Table, String, Trie, Simulation
• 2332. Count Lattice Points Inside a Circle - MediumTopics: Array, Hash Table, Math, Geometry, Enumeration
• 1257. Rank Transform of a Matrix - HardTopics: Array, Union Find, Graph, Topological Sort, Sorting, Matrix
• 2027. Maximum Number of Removable Characters - MediumTopics: Array, Two Pointers, String, Binary Search
• 3413. Find The First Player to win K Games in a Row - MediumTopics: Array, Simulation
• 1212. Sequential Digits - MediumTopics: Enumeration
• 2182. Find the Minimum and Maximum Number of Nodes Between Critical Points - MediumTopics: Linked List
• 935. Orderly Queue - HardTopics: Math, String, Sorting
• 1560. Number of Students Doing Homework at a Given Time - EasyTopics: Array
• 3908. Minimum Time for K Connected Components - MediumTopics: Binary Search, Union Find, Graph, Sorting
• 3912. Hexadecimal and Hexatrigesimal Conversion - EasyTopics: Math, String
• 2551. Apply Operations to an Array - EasyTopics: Array, Two Pointers, Simulation
• 3106. Length of the Longest Subsequence That Sums to Target - MediumTopics: Array, Dynamic Programming
• 2810. Collecting Chocolates - MediumTopics: Array, Enumeration
• 1908. Recyclable and Low Fat Products - EasyTopics: Database
• 2054. The Number of the Smallest Unoccupied Chair - MediumTopics: Array, Hash Table, Heap (Priority Queue)
• 2173. Number of Valid Words in a Sentence - EasyTopics: String
• 2563. Split Message Based on Limit - HardTopics: String, Binary Search, Enumeration
• 3241. Divide Array Into Arrays With Max Difference - MediumTopics: Array, Greedy, Sorting
• 1057. Numbers With Repeated Digits - HardTopics: Math, Dynamic Programming
• 1732. Minimum One Bit Operations to Make Integers Zero - HardTopics: Dynamic Programming, Bit Manipulation, Memoization
• 1080. Camelcase Matching - MediumTopics: Array, Two Pointers, String, Trie, String Matching
• 2083. Three Divisors - EasyTopics: Math, Enumeration, Number Theory
• 1885. Count Number of Homogenous Substrings - MediumTopics: Math, String
• 2650. Split With Minimum Sum - EasyTopics: Math, Greedy, Sorting
• 2681. Put Marbles in Bags - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 1112. Find Words That Can Be Formed by Characters - EasyTopics: Array, Hash Table, String, Counting
• 1585. The kth Factor of n - MediumTopics: Math, Number Theory
• 2289. Minimum Operations to Make the Array Alternating - MediumTopics: Array, Hash Table, Greedy, Counting
• 1292. Immediate Food Delivery II - MediumTopics: Database
• 3501. Delete Nodes From Linked List Present in Array - MediumTopics: Array, Hash Table, Linked List
• 1122. Longest Duplicate Substring - HardTopics: String, Binary Search, Sliding Window, Rolling Hash, Suffix Array, Hash Function
• 3973. Flip Square Submatrix Vertically - EasyTopics: Array, Two Pointers, Matrix
• 1526. HTML Entity Parser - MediumTopics: Hash Table, String
• 820. Find Eventual Safe States - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 3398. Make a Square with the Same Color - EasyTopics: Array, Matrix, Enumeration
• 2539. Minimum Number of Operations to Make Arrays Similar - HardTopics: Array, Greedy, Sorting
• 546. Remove Boxes - HardTopics: Array, Dynamic Programming, Memoization
• 1667. Find Kth Bit in Nth Binary String - MediumTopics: String, Recursion, Simulation
• 3942. Find Drivers with Improved Fuel Efficiency - MediumTopics: Database
• 1889. Check if Number is a Sum of Powers of Three - MediumTopics: Math
• 3511. Find the Winning Player in Coin Game - EasyTopics: Math, Simulation, Game Theory
• 3869. Smallest Index With Digit Sum Equal to Index - EasyTopics: Array, Math
• 1892. Find Total Time Spent by Each Employee - EasyTopics: Database
• 2979. Maximize the Profit as the Salesman - MediumTopics: Array, Hash Table, Binary Search, Dynamic Programming, Sorting
• 1767. Design Front Middle Back Queue - MediumTopics: Array, Linked List, Design, Queue, Data Stream
• 2470. Removing Stars From a String - MediumTopics: String, Stack, Simulation
• 164. Maximum Gap - MediumTopics: Array, Sorting, Bucket Sort, Radix Sort
• 3399. Find the Integer Added to Array II - MediumTopics: Array, Two Pointers, Sorting, Enumeration
• 3930. Longest Palindromic Path in Graph - HardTopics: String, Dynamic Programming, Bit Manipulation, Graph, Bitmask
• 1183. Statistics from a Large Sample - MediumTopics: Array, Math, Probability and Statistics
• 3172. Divisible and Non-divisible Sums Difference - EasyTopics: Math
• 2217. Step-By-Step Directions From a Binary Tree Node to Another - MediumTopics: String, Tree, Depth-First Search, Binary Tree
• 1427. All Elements in Two Binary Search Trees - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Sorting, Binary Tree
• 3882. Partition Array for Maximum XOR and AND - HardTopics: Array, Math, Greedy, Enumeration
• 2582. Minimum Score of a Path Between Two Cities - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 627. Swap Salary - EasyTopics: Database
• 1824. Maximum Number of Eaten Apples - MediumTopics: Array, Greedy, Heap (Priority Queue)
• 2238. A Number After a Double Reversal - EasyTopics: Math
• 2463. Minimum Recolors to Get K Consecutive Black Blocks - EasyTopics: String, Sliding Window
• 2265. Partition Array According to Given Pivot - MediumTopics: Array, Two Pointers, Simulation
• 2497. Maximum Matching of Players With Trainers - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 1548. Check If All 1's Are at Least Length K Places Away - EasyTopics: Array
• 3931. Process String with Special Operations I - MediumTopics: String, Simulation
• 3939. Process String with Special Operations II - HardTopics: String, Simulation
• 1086. Divisor Game - EasyTopics: Math, Dynamic Programming, Brainteaser, Game Theory
• 3494. Minimum Cost for Cutting Cake I - MediumTopics: Array, Dynamic Programming, Greedy, Sorting
• 2888. Minimum Index of a Valid Split - MediumTopics: Array, Hash Table, Sorting
• 1509. Replace Employee ID With The Unique Identifier - EasyTopics: Database
• 1065. Binary String With Substrings Representing 1 To N - MediumTopics: Hash Table, String, Bit Manipulation, Sliding Window
• 2603. Reward Top K Students - MediumTopics: Array, Hash Table, String, Sorting, Heap (Priority Queue)
• 2833. Count Zero Request Servers - MediumTopics: Array, Hash Table, Sliding Window, Sorting
• 1928. Number of Orders in the Backlog - MediumTopics: Array, Heap (Priority Queue), Simulation
• 2450. Minimum Replacements to Sort the Array - HardTopics: Array, Math, Greedy
• 3594. Identify the Largest Outlier in an Array - MediumTopics: Array, Hash Table, Counting, Enumeration
• 3225. Length of Longest Subarray With at Most K Frequency - MediumTopics: Array, Hash Table, Sliding Window
• 1952. Minimum Sideway Jumps - MediumTopics: Array, Dynamic Programming, Greedy
• 1451. Minimum Number of Taps to Open to Water a Garden - HardTopics: Array, Dynamic Programming, Greedy
• 853. Most Profit Assigning Work - MediumTopics: Array, Two Pointers, Binary Search, Greedy, Sorting
• 1223. Graph Connectivity With Threshold - HardTopics: Array, Math, Union Find, Number Theory
• 2619. Categorize Box According to Criteria - EasyTopics: Math
• 3961. Find Students with Study Spiral Pattern - HardTopics:
• 2026. Merge Triplets to Form Target Triplet - MediumTopics: Array, Greedy
• 2678. Design Graph With Shortest Path Calculator - HardTopics: Graph, Design, Heap (Priority Queue), Shortest Path
• 3076. Get the Size of a DataFrame - EasyTopics:
• 1161. Project Employees I - EasyTopics: Database
• 748. Largest Number At Least Twice of Others - EasyTopics: Array, Sorting
• 1008. Binary Tree Cameras - HardTopics: Dynamic Programming, Tree, Depth-First Search, Binary Tree
• 692. Top K Frequent Words - MediumTopics: Array, Hash Table, String, Trie, Sorting, Heap (Priority Queue), Bucket Sort, Counting
• 3937. Number of Integers With Popcount-Depth Equal to K I - HardTopics: Math, Dynamic Programming, Combinatorics
• 1145. Number of Submatrices That Sum to Target - HardTopics: Array, Hash Table, Matrix, Prefix Sum
• 2877. Shortest String That Contains Three Strings - MediumTopics: String, Greedy, Enumeration
• 3788. Maximum Unique Subarray Sum After Deletion - EasyTopics: Array, Hash Table, Greedy
• 3540. Hash Divided String - MediumTopics: String, Simulation
• 869. Similar String Groups - HardTopics: Array, Hash Table, String, Depth-First Search, Breadth-First Search, Union Find
• 2403. Count Unreachable Pairs of Nodes in an Undirected Graph - MediumTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 3270. Minimum Moves to Capture The Queen - MediumTopics: Math, Enumeration
• 3657. Check if Grid can be Cut into Sections - MediumTopics: Array, Sorting
• 649. Dota2 Senate - MediumTopics: String, Greedy, Queue
• 489. Kth Smallest Instructions - HardTopics: Array, Math, Dynamic Programming, Combinatorics
• 1700. Minimum Time to Make Rope Colorful - MediumTopics: Array, String, Dynamic Programming, Greedy
• 2494. Sum of Prefix Scores of Strings - HardTopics: Array, String, Trie, Counting
• 2108. Minimize the Difference Between Target and Chosen Elements - MediumTopics: Array, Dynamic Programming, Matrix
• 1987. Substrings of Size Three with Distinct Characters - EasyTopics: Hash Table, String, Sliding Window, Counting
• 2134. Maximize the Confusion of an Exam - MediumTopics: String, Binary Search, Sliding Window, Prefix Sum
• 2503. Longest Subarray With Maximum Bitwise AND - MediumTopics: Array, Bit Manipulation, Brainteaser
• 1440. Convert Integer to the Sum of Two No-Zero Integers - EasyTopics: Math
• 1562. People Whose List of Favorite Companies Is Not a Subset of Another List - MediumTopics: Array, Hash Table, String
• 3885. Count Special Triplets - MediumTopics: Array, Hash Table, Counting
• 2146. Check if Word Can Be Placed In Crossword - MediumTopics: Array, Matrix, Enumeration
• 1626. Can Make Arithmetic Progression From Sequence - EasyTopics: Array, Sorting
• 1923. Sentence Similarity III - MediumTopics: Array, Two Pointers, String
• 3701. Minimum Cost Good Caption - HardTopics: String, Dynamic Programming
• 2889. Number of Black Blocks - MediumTopics: Array, Hash Table, Enumeration
• 2166. Number of Valid Move Combinations On Chessboard - HardTopics: Array, String, Backtracking, Simulation
• 1311. Largest Magic Square - MediumTopics: Array, Matrix, Prefix Sum
• 1001. N-Repeated Element in Size 2N Array - EasyTopics: Array, Hash Table
• 1519. Minimum Subsequence in Non-Increasing Order - EasyTopics: Array, Greedy, Sorting
• 2914. Find the Safest Path in a Grid - MediumTopics: Array, Binary Search, Breadth-First Search, Union Find, Heap (Priority Queue), Matrix
• 2356. Largest Combination With Bitwise AND Greater Than Zero - MediumTopics: Array, Hash Table, Bit Manipulation, Counting
• 2034. Minimum Absolute Difference Queries - MediumTopics: Array, Hash Table
• 1445. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold - MediumTopics: Array, Sliding Window
• 1303. Minimum Moves to Reach Target Score - MediumTopics: Math, Greedy
• 3414. Find Number of Ways to Reach the K-th Stair - HardTopics: Math, Dynamic Programming, Bit Manipulation, Memoization, Combinatorics
• 2857. Total Distance Traveled - EasyTopics: Math, Simulation
• 2037. Count Square Sum Triples - EasyTopics: Math, Enumeration
• 2395. Longest Binary Subsequence Less Than or Equal to K - MediumTopics: String, Dynamic Programming, Greedy, Memoization
• 1728. Fancy Sequence - HardTopics: Math, Design, Segment Tree
• 3868. Find Maximum Area of a Triangle - MediumTopics: Array, Hash Table, Math, Greedy, Geometry, Enumeration
• 2197. Decode the Slanted Ciphertext - MediumTopics: String, Simulation
• 2615. Make Number of Distinct Characters Equal - MediumTopics: Hash Table, String, Counting
• 1827. Invalid Tweets - EasyTopics: Database
• 1986. Largest Color Value in a Directed Graph - HardTopics: Hash Table, Dynamic Programming, Graph, Topological Sort, Memoization, Counting
• 85. Maximal Rectangle - HardTopics: Array, Dynamic Programming, Stack, Matrix, Monotonic Stack
• 3906. Kth Smallest Path XOR Sum - HardTopics: Array, Tree, Depth-First Search, Ordered Set
• 2832. Find the Longest Equal Subarray - MediumTopics: Array, Hash Table, Binary Search, Sliding Window
• 1216. Print Zero Even Odd - MediumTopics: Concurrency
• 851. Goat Latin - EasyTopics: String
• 1766. Minimum Number of Removals to Make Mountain Array - HardTopics: Array, Binary Search, Dynamic Programming, Greedy
• 1341. Split a String in Balanced Strings - EasyTopics: String, Greedy, Counting
• 1186. Building H2O - MediumTopics: Concurrency
• 479. Largest Palindrome Product - HardTopics: Math, Enumeration
• 1273. Compare Strings by Frequency of the Smallest Character - MediumTopics: Array, Hash Table, String, Binary Search, Sorting
• 2573. Remove Nodes From Linked List - MediumTopics: Linked List, Stack, Recursion, Monotonic Stack
• 3195. Separate Black and White Balls - MediumTopics: Two Pointers, String, Greedy
• 3321. Type of Triangle - EasyTopics: Array, Math, Sorting
• 3388. Right Triangles - MediumTopics: Array, Hash Table, Math, Combinatorics, Counting
• 401. Binary Watch - EasyTopics: Backtracking, Bit Manipulation
• 1038. Number of Squareful Arrays - HardTopics: Array, Hash Table, Math, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 2816. Lexicographically Smallest Palindrome - EasyTopics: Two Pointers, String, Greedy
• 1905. Design Authentication Manager - MediumTopics: Hash Table, Linked List, Design, Doubly-Linked List
• 2305. Append K Integers With Minimal Sum - MediumTopics: Array, Math, Greedy, Sorting
• 3405. Count the Number of Special Characters II - MediumTopics: Hash Table, String
• 2018. Minimum Space Wasted From Packaging - HardTopics: Array, Binary Search, Sorting, Prefix Sum
• 1179. Game Play Analysis I - EasyTopics: Database
• 915. Generate Random Point in a Circle - MediumTopics: Math, Geometry, Rejection Sampling, Randomized
• 3600. Find the K-th Character in String Game I - EasyTopics: Math, Bit Manipulation, Recursion, Simulation
• 754. Cracking the Safe - HardTopics: Depth-First Search, Graph, Eulerian Circuit
• 3303. Find Beautiful Indices in the Given Array II - HardTopics: Two Pointers, String, Binary Search, Rolling Hash, String Matching, Hash Function
• 3786. Longest Palindromic Subsequence After at Most K Operations - MediumTopics: String, Dynamic Programming
• 2232. Adding Spaces to a String - MediumTopics: Array, Two Pointers, String, Simulation
• 400. Nth Digit - MediumTopics: Math, Binary Search
• 263. Ugly Number - EasyTopics: Math
• 3552. Find the Largest Palindrome Divisible by K - HardTopics: Math, String, Dynamic Programming, Greedy, Number Theory
• 900. Reordered Power of 2 - MediumTopics: Hash Table, Math, Sorting, Counting, Enumeration
• 1633. Minimum Number of Increments on Subarrays to Form a Target Array - HardTopics: Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
• 1104. Coloring A Border - MediumTopics: Array, Depth-First Search, Breadth-First Search, Matrix
• 3736. Find Valid Pair of Adjacent Digits in String - EasyTopics: Hash Table, String, Counting
• 918. Reachable Nodes In Subdivided Graph - HardTopics: Graph, Heap (Priority Queue), Shortest Path
• 1376. Selling Pieces of Wood - HardTopics: Array, Dynamic Programming, Memoization
• 2149. Remove Colored Pieces if Both Neighbors are the Same Color - MediumTopics: Math, String, Greedy, Game Theory
• 1433. Encrypt and Decrypt Strings - HardTopics: Array, Hash Table, String, Design, Trie
• 1497. Design a Stack With Increment Operation - MediumTopics: Array, Stack, Design
• 1327. Last Person to Fit in the Bus - MediumTopics: Database
• 491. Non-decreasing Subsequences - MediumTopics: Array, Hash Table, Backtracking, Bit Manipulation
• 3950. Maximum K to Sort a Permutation - MediumTopics:
• 3024. String Transformation - HardTopics: Math, String, Dynamic Programming, String Matching
• 3697. Minimum Increments for Target Multiples in an Array - HardTopics: Array, Math, Dynamic Programming, Bit Manipulation, Number Theory, Bitmask
• 1466. Jump Game V - HardTopics: Array, Dynamic Programming, Sorting
• 1557. Check If a String Contains All Binary Codes of Size K - MediumTopics: Hash Table, String, Bit Manipulation, Rolling Hash, Hash Function
• 3776. Find Minimum Cost to Remove Array Elements - MediumTopics: Array, Dynamic Programming
• 654. Maximum Binary Tree - MediumTopics: Array, Divide and Conquer, Stack, Tree, Monotonic Stack, Binary Tree
• 1939. Queries on Number of Points Inside a Circle - MediumTopics: Array, Math, Geometry
• 3936. Split Array by Prime Indices - MediumTopics: Array, Math, Number Theory
• 2779. Number of Adjacent Elements With the Same Color - MediumTopics: Array
• 830. Largest Triangle Area - EasyTopics: Array, Math, Geometry
• 1182. Game Play Analysis IV - MediumTopics: Database
• 2800. Minimum String Length After Removing Substrings - EasyTopics: String, Stack, Simulation
• 2299. Merge Nodes in Between Zeros - MediumTopics: Linked List, Simulation
• 1533. Display Table of Food Orders in a Restaurant - MediumTopics: Array, Hash Table, String, Sorting, Ordered Set
• 2116. Count Number of Pairs With Absolute Difference K - EasyTopics: Array, Hash Table, Counting
• 3580. Find the Occurrence of First Almost Equal Substring - HardTopics: String, String Matching
• 1520. Number of Steps to Reduce a Number in Binary Representation to One - MediumTopics: String, Bit Manipulation, Simulation
• 2040. Minimum Cost to Reach Destination in Time - HardTopics: Array, Dynamic Programming, Graph
• 2112. Minimum Difference Between Highest and Lowest of K Scores - EasyTopics: Array, Sliding Window, Sorting
• 3336. Water Bottles II - MediumTopics: Math, Simulation
• 3382. Find the Number of Subarrays Where Boundary Elements Are Maximum - HardTopics: Array, Binary Search, Stack, Monotonic Stack
• 3794. Find the Minimum Amount of Time to Brew Potions - MediumTopics: Array, Simulation, Prefix Sum
• 3819. Count Covered Buildings - MediumTopics: Array, Hash Table, Sorting
• 2465. Shifting Letters II - MediumTopics: Array, String, Prefix Sum
• 1725. Number of Sets of K Non-Overlapping Line Segments - MediumTopics: Math, Dynamic Programming, Combinatorics
• 2114. Minimum Number of Work Sessions to Finish the Tasks - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 2012. Process Tasks Using Servers - MediumTopics: Array, Heap (Priority Queue)
• 3720. Minimize the Maximum Edge Weight of Graph - MediumTopics: Binary Search, Depth-First Search, Breadth-First Search, Graph, Shortest Path
• 2614. Maximum Count of Positive Integer and Negative Integer - EasyTopics: Array, Binary Search, Counting
• 3262. Find Polygon With the Largest Perimeter - MediumTopics: Array, Greedy, Sorting, Prefix Sum
• 1017. Odd Even Jump - HardTopics: Array, Dynamic Programming, Stack, Sorting, Monotonic Stack, Ordered Set
• 3677. Maximum Amount of Money Robot Can Earn - MediumTopics: Array, Dynamic Programming, Matrix
• 1690. Maximum Length of Subarray With Positive Product - MediumTopics: Array, Dynamic Programming, Greedy
• 669. Trim a Binary Search Tree - MediumTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 3373. Maximum Prime Difference - MediumTopics: Array, Math, Number Theory
• 195. Tenth Line - EasyTopics: Shell
• 2361. Calculate Digit Sum of a String - EasyTopics: String, Simulation
• 3898. Seasonal Sales Analysis - MediumTopics: Database
• 2416. Evaluate Boolean Binary Tree - EasyTopics: Tree, Depth-First Search, Binary Tree
• 960. Minimize Malware Spread - HardTopics: Array, Hash Table, Depth-First Search, Breadth-First Search, Union Find, Graph
• 687. Longest Univalue Path - MediumTopics: Tree, Depth-First Search, Binary Tree
• 3891. Find Category Recommendation Pairs - HardTopics: Database
• 282. Expression Add Operators - HardTopics: Math, String, Backtracking
• 979. DI String Match - EasyTopics: Array, Two Pointers, String, Greedy
• 2758. Check if Object Instance of Class - MediumTopics:
• 3872. Find Most Frequent Vowel and Consonant - EasyTopics: Hash Table, String, Counting
• 2023. Design Movie Rental System - HardTopics: Array, Hash Table, Design, Heap (Priority Queue), Ordered Set
• 3690. Smallest Substring With Identical Characters I - HardTopics: Array, Binary Search, Enumeration
• 2215. Finding 3-Digit Even Numbers - EasyTopics: Array, Hash Table, Sorting, Enumeration
• 863. Sum of Distances in Tree - HardTopics: Dynamic Programming, Tree, Depth-First Search, Graph
• 183. Customers Who Never Order - EasyTopics: Database
• 2575. Minimum Cuts to Divide a Circle - EasyTopics: Math, Geometry
• 1915. Check if One String Swap Can Make Strings Equal - EasyTopics: Hash Table, String, Counting
• 3105. Minimum Edge Reversals So Every Node Is Reachable - HardTopics: Dynamic Programming, Depth-First Search, Breadth-First Search, Graph
• 1927. Maximum Ascending Subarray Sum - EasyTopics: Array
• 2518. The Employee That Worked on the Longest Task - EasyTopics: Array
• 1625. Group Sold Products By The Date - EasyTopics: Database
• 902. Minimum Number of Refueling Stops - HardTopics: Array, Dynamic Programming, Greedy, Heap (Priority Queue)
• 1904. Second Largest Digit in a String - EasyTopics: Hash Table, String
• 1230. Maximum of Absolute Value Expression - MediumTopics: Array, Math
• 1545. Form Largest Integer With Digits That Add up to Target - HardTopics: Array, Dynamic Programming
• 1884. Minimum Changes To Make Alternating Binary String - EasyTopics: String
• 3965. Earliest Finish Time for Land and Water Rides I - EasyTopics: Array, Two Pointers, Binary Search, Greedy, Sorting
• 2309. Maximize Number of Subsequences in a String - MediumTopics: String, Greedy, Prefix Sum
• 3900. Find Weighted Median Node in Tree - HardTopics: Array, Binary Search, Dynamic Programming, Tree, Depth-First Search
• 2292. Counting Words With a Given Prefix - EasyTopics: Array, String, String Matching
• 2177. Check Whether Two Strings are Almost Equivalent - EasyTopics: Hash Table, String, Counting
• 1990. Get Biggest Three Rhombus Sums in a Grid - MediumTopics: Array, Math, Sorting, Heap (Priority Queue), Matrix, Prefix Sum
• 3434. Find the Number of Distinct Colors Among the Balls - MediumTopics: Array, Hash Table, Simulation
• 942. Super Palindromes - HardTopics: Math, String, Enumeration
• 2025. Redistribute Characters to Make All Strings Equal - EasyTopics: Hash Table, String, Counting
• 2205. Find Good Days to Rob the Bank - MediumTopics: Array, Dynamic Programming, Prefix Sum
• 1675. Magnetic Force Between Two Balls - MediumTopics: Array, Binary Search, Sorting
• 2237. Longest Palindrome by Concatenating Two Letter Words - MediumTopics: Array, Hash Table, String, Greedy, Counting
• 3809. Properties Graph - MediumTopics: Array, Hash Table, Depth-First Search, Breadth-First Search, Union Find, Graph
• 3139. Subarrays Distinct Element Sum of Squares II - HardTopics: Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
• 757. Pyramid Transition Matrix - MediumTopics: Bit Manipulation, Depth-First Search, Breadth-First Search
• 1338. Queries Quality and Percentage - EasyTopics: Database
• 3483. Alternating Groups II - MediumTopics: Array, Sliding Window
• 264. Ugly Number II - MediumTopics: Hash Table, Math, Dynamic Programming, Heap (Priority Queue)
• 3251. Maximum Area of Longest Diagonal Rectangle - EasyTopics: Array
• 3850. Equal Sum Grid Partition II - HardTopics: Array, Hash Table, Matrix, Enumeration, Prefix Sum
• 1727. Cat and Mouse II - HardTopics: Array, Math, Dynamic Programming, Graph, Topological Sort, Memoization, Matrix, Game Theory
• 2642. Time to Cross a Bridge - HardTopics: Array, Heap (Priority Queue), Simulation
• 1837. Daily Leads and Partners - EasyTopics: Database
• 1808. Stone Game VII - MediumTopics: Array, Math, Dynamic Programming, Game Theory
• 2419. Subarray With Elements Greater Than Varying Threshold - HardTopics: Array, Stack, Union Find, Monotonic Stack
• 2821. Timeout Cancellation - EasyTopics:
• 453. Minimum Moves to Equal Array Elements - MediumTopics: Array, Math
• 1657. Find the Winner of an Array Game - MediumTopics: Array, Simulation
• 2954. Maximum Sum of Almost Unique Subarray - MediumTopics: Array, Hash Table, Sliding Window
• 2677. Cousins in Binary Tree II - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 2324. Find Triangular Sum of an Array - MediumTopics: Array, Math, Simulation, Combinatorics
• 821. Bricks Falling When Hit - HardTopics: Array, Union Find, Matrix
• 304. Range Sum Query 2D - Immutable - MediumTopics: Array, Design, Matrix, Prefix Sum
• 3469. Maximum Height of a Triangle - EasyTopics: Array, Enumeration
• 3562. Maximum Score of Non-overlapping Intervals - HardTopics: Array, Binary Search, Dynamic Programming, Sorting
• 388. Longest Absolute File Path - MediumTopics: String, Stack, Depth-First Search
• 2754. Maximum Strength of a Group - MediumTopics: Array, Dynamic Programming, Backtracking, Greedy, Bit Manipulation, Sorting, Enumeration
• 2708. Find the String with LCP - HardTopics: Array, String, Dynamic Programming, Greedy, Union Find, Matrix
• 585. Investments in 2016 - MediumTopics: Database
• 3462. Vowels Game in a String - MediumTopics: Math, String, Brainteaser, Game Theory
• 3236. Smallest Missing Integer Greater Than Sequential Prefix Sum - EasyTopics: Array, Hash Table, Sorting
• 2737. Row With Maximum Ones - EasyTopics: Array, Matrix
• 3292. Earliest Second to Mark Indices I - MediumTopics: Array, Binary Search
• 3907. Count Prime-Gap Balanced Subarrays - MediumTopics: Array, Math, Queue, Sliding Window, Number Theory, Monotonic Queue
• 1762. Furthest Building You Can Reach - MediumTopics: Array, Greedy, Heap (Priority Queue)
• 3250. Maximum Square Area by Removing Fences From a Field - MediumTopics: Array, Hash Table, Enumeration
• 2892. Check if Array is Good - EasyTopics: Array, Hash Table, Sorting
• 2239. Execution of All Suffix Instructions Staying in a Grid - MediumTopics: String, Simulation
• 1566. Check If a Word Occurs As a Prefix of Any Word in a Sentence - EasyTopics: Two Pointers, String, String Matching
• 2384. Root Equals Sum of Children - EasyTopics: Tree, Binary Tree
• 2659. Number of Even and Odd Bits - EasyTopics: Bit Manipulation
• 2731. Memoize - MediumTopics:
• 3876. Transform Array to All Equal Elements - MediumTopics: Array, Greedy
• 1731. Even Odd Tree - MediumTopics: Tree, Breadth-First Search, Binary Tree
• 2256. Count Words Obtained After Adding a Letter - MediumTopics: Array, Hash Table, String, Bit Manipulation, Sorting
• 2447. Merge Similar Items - EasyTopics: Array, Hash Table, Sorting, Ordered Set
• 1111. Minimum Score Triangulation of Polygon - MediumTopics: Array, Dynamic Programming
• 3918. Check Divisibility by Digit Sum and Product - EasyTopics: Math
• 3463. Alternating Groups I - EasyTopics: Array, Sliding Window
• 1811. Fix Names in a Table - EasyTopics: Database
• 2651. Count Ways to Group Overlapping Ranges - MediumTopics: Array, Sorting
• 1473. Find the Longest Substring Containing Vowels in Even Counts - MediumTopics: Hash Table, String, Bit Manipulation, Prefix Sum
• 2834. Relocate Marbles - MediumTopics: Array, Hash Table, Sorting, Simulation
• 2355. Maximum Consecutive Floors Without Special Floors - MediumTopics: Array, Sorting
• 1716. Maximum Non Negative Product in a Matrix - MediumTopics: Array, Dynamic Programming, Matrix
• 1894. Merge Strings Alternately - EasyTopics: Two Pointers, String
• 2680. Count Collisions of Monkeys on a Polygon - MediumTopics: Math, Recursion
• 3688. Maximize Subarray Sum After Removing All Occurrences of One Element - HardTopics: Array, Dynamic Programming, Segment Tree
• 2251. Number of Ways to Divide a Long Corridor - HardTopics: Math, String, Dynamic Programming
• 3186. Minimum Sum of Mountain Triplets II - MediumTopics: Array
• 1297. Maximum Number of Balloons - EasyTopics: Hash Table, String, Counting
• 1660. Thousand Separator - EasyTopics: String
• 3334. Apple Redistribution into Boxes - EasyTopics: Array, Greedy, Sorting
• 2592. Minimum Total Cost to Make Arrays Unequal - HardTopics: Array, Hash Table, Greedy, Counting
• 3335. Minimum Operations to Write the Letter Y on a Grid - MediumTopics: Array, Hash Table, Matrix, Counting
• 3391. Maximum Difference Score in a Grid - MediumTopics: Array, Dynamic Programming, Matrix
• 3450. Find the Child Who Has the Ball After K Seconds - EasyTopics: Math, Simulation
• 2455. Node With Highest Edge Score - MediumTopics: Hash Table, Graph
• 3920. Minimum Stability Factor of Array - HardTopics: Array, Math, Binary Search, Greedy, Segment Tree, Number Theory
• 3215. Matrix Similarity After Cyclic Shifts - EasyTopics: Array, Math, Matrix, Simulation
• 1530. Check If a String Can Break Another String - MediumTopics: String, Greedy, Sorting
• 958. Sort Array By Parity II - EasyTopics: Array, Two Pointers, Sorting
• 1375. Find Palindrome With Fixed Length - MediumTopics: Array, Math
• 3560. Maximum Number of Moves to Kill All Pawns - HardTopics: Array, Math, Bit Manipulation, Breadth-First Search, Game Theory, Bitmask
• 3647. Zero Array Transformation III - MediumTopics: Array, Greedy, Sorting, Heap (Priority Queue), Prefix Sum
• 1185. Find in Mountain Array - HardTopics: Array, Binary Search, Interactive
• 1242. Matrix Block Sum - MediumTopics: Array, Matrix, Prefix Sum
• 334. Increasing Triplet Subsequence - MediumTopics: Array, Greedy
• 3163. Subarrays Distinct Element Sum of Squares I - EasyTopics: Array, Hash Table
• 3634. Find Mirror Score of a String - MediumTopics: Hash Table, String, Stack, Simulation
• 1806. Count of Matches in Tournament - EasyTopics: Math, Simulation
• 3879. Find Minimum Log Transportation Cost - EasyTopics: Math
• 1245. User Activity for the Past 30 Days I - EasyTopics: Database
• 2527. Count Subarrays With Fixed Bounds - HardTopics: Array, Queue, Sliding Window, Monotonic Queue
• 672. Bulb Switcher II - MediumTopics: Math, Bit Manipulation, Depth-First Search, Breadth-First Search
• 1627. Last Moment Before All Ants Fall Out of a Plank - MediumTopics: Array, Brainteaser, Simulation
• 3384. Minimum Number of Operations to Make Word K-Periodic - MediumTopics: Hash Table, String, Counting
• 1630. Count Odd Numbers in an Interval Range - EasyTopics: Math
• 3958. Minimum Removals to Balance Array - MediumTopics: Array, Sliding Window, Sorting
• 2442. Number of Arithmetic Triplets - EasyTopics: Array, Hash Table, Two Pointers, Enumeration
• 1953. Finding MK Average - HardTopics: Design, Queue, Heap (Priority Queue), Data Stream, Ordered Set
• 919. Projection Area of 3D Shapes - EasyTopics: Array, Math, Geometry, Matrix
• 2255. Minimum Swaps to Group All 1's Together II - MediumTopics: Array, Sliding Window
• 1918. Maximum Score of a Good Subarray - HardTopics: Array, Two Pointers, Binary Search, Stack, Monotonic Stack
• 2576. Minimum Penalty for a Shop - MediumTopics: String, Prefix Sum
• 3310. Count the Number of Houses at a Certain Distance II - HardTopics: Graph, Prefix Sum
• 3309. Count Prefix and Suffix Pairs I - EasyTopics: Array, String, Trie, Rolling Hash, String Matching, Hash Function
• 2881. Split Strings by Separator - EasyTopics: Array, String
• 1983. Maximum Population Year - EasyTopics: Array, Counting, Prefix Sum
• 2717. Collect Coins in a Tree - HardTopics: Array, Tree, Graph, Topological Sort
• 3226. Minimum Number Game - EasyTopics: Array, Sorting, Heap (Priority Queue), Simulation
• 1097. Stream of Characters - HardTopics: Array, String, Design, Trie, Data Stream
• 1968. Maximum Building Height - HardTopics: Array, Math, Sorting
• 2229. Maximum Fruits Harvested After at Most K Steps - HardTopics: Array, Binary Search, Sliding Window, Prefix Sum
• 2131. Smallest Missing Genetic Value in Each Subtree - HardTopics: Dynamic Programming, Tree, Depth-First Search, Union Find
• 3271. Count the Number of Houses at a Certain Distance I - MediumTopics: Breadth-First Search, Graph, Prefix Sum
• 1434. Decrypt String from Alphabet to Integer Mapping - EasyTopics: String
• 802. K-th Smallest Prime Fraction - MediumTopics: Array, Two Pointers, Binary Search, Sorting, Heap (Priority Queue)
• 1576. Reorder Routes to Make All Paths Lead to the City Zero - MediumTopics: Depth-First Search, Breadth-First Search, Graph
• 2284. Smallest Value of the Rearranged Number - MediumTopics: Math, Sorting
• 1645. Find a Value of a Mysterious Function Closest to Target - HardTopics: Array, Binary Search, Bit Manipulation, Segment Tree
• 331. Verify Preorder Serialization of a Binary Tree - MediumTopics: String, Stack, Tree, Binary Tree
• 1435. XOR Queries of a Subarray - MediumTopics: Array, Bit Manipulation, Prefix Sum
• 1714. Rearrange Spaces Between Words - EasyTopics: String
• 501. Find Mode in Binary Search Tree - EasyTopics: Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 3933. Minimum Jumps to Reach End via Prime Teleportation - MediumTopics: Array, Hash Table, Math, Breadth-First Search, Number Theory
• 2390. Naming a Company - HardTopics: Array, Hash Table, String, Bit Manipulation, Enumeration
• 1071. Binary Prefix Divisible By 5 - EasyTopics: Array, Bit Manipulation
• 3279. Alice and Bob Playing Flower Game - MediumTopics: Math
• 1661. Minimum Number of Vertices to Reach All Nodes - MediumTopics: Graph
• 1636. Number of Substrings With Only 1s - MediumTopics: Math, String
• 2404. Number of Distinct Roll Sequences - HardTopics: Dynamic Programming, Memoization
• 887. Minimum Cost to Hire K Workers - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 1543. Simplified Fractions - MediumTopics: Math, String, Number Theory
• 1329. Minimum Cost to Move Chips to The Same Position - EasyTopics: Array, Math, Greedy
• 1913. Make the XOR of All Segments Equal to Zero - HardTopics: Array, Dynamic Programming, Bit Manipulation
• 2436. Make Array Zero by Subtracting Equal Amounts - EasyTopics: Array, Hash Table, Greedy, Sorting, Heap (Priority Queue), Simulation
• 1431. All Ancestors of a Node in a Directed Acyclic Graph - MediumTopics: Depth-First Search, Breadth-First Search, Graph, Topological Sort
• 1554. Minimum Time to Collect All Apples in a Tree - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search
• 539. Minimum Time Difference - MediumTopics: Array, Math, String, Sorting
• 2978. Check if Strings Can be Made Equal With Operations II - MediumTopics: Hash Table, String, Sorting
• 2640. Maximum Number of Integers to Choose From a Range I - MediumTopics: Array, Hash Table, Binary Search, Greedy, Sorting
• 3881. Minimize Maximum Component Cost - MediumTopics: Binary Search, Union Find, Graph, Sorting
• 1934. Evaluate the Bracket Pairs of a String - MediumTopics: Array, Hash Table, String
• 440. K-th Smallest in Lexicographical Order - HardTopics: Trie
• 2699. Count the Number of Fair Pairs - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 2788. Design Cancellable Function - HardTopics:
• 2176. Parallel Courses III - HardTopics: Array, Dynamic Programming, Graph, Topological Sort
• 955. Complete Binary Tree Inserter - MediumTopics: Tree, Breadth-First Search, Design, Binary Tree
• 2513. Number of Pairs Satisfying Inequality - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 2184. Check if an Original String Exists Given Two Encoded Strings - HardTopics: String, Dynamic Programming
• 1049. Minimum Domino Rotations For Equal Row - MediumTopics: Array, Greedy
• 3456. Find the Maximum Length of a Good Subsequence I - MediumTopics: Array, Hash Table, Dynamic Programming
• 3702. Maximum Subarray With Equal Products - EasyTopics: Array, Math, Sliding Window, Enumeration, Number Theory
• 2765. Make Array Empty - HardTopics: Array, Binary Search, Greedy, Binary Indexed Tree, Segment Tree, Sorting, Ordered Set
• 1307. Ugly Number III - MediumTopics: Math, Binary Search, Combinatorics, Number Theory
• 1511. Count Number of Teams - MediumTopics: Array, Dynamic Programming, Binary Indexed Tree, Segment Tree
• 2412. Minimum Amount of Time to Fill Cups - EasyTopics: Array, Greedy, Sorting, Heap (Priority Queue)
• 3345. Find the Sum of the Power of All Subsequences - HardTopics: Array, Dynamic Programming
• 3000. Minimum Absolute Difference Between Elements With Constraint - MediumTopics: Array, Binary Search, Ordered Set
• 3447. Clear Digits - EasyTopics: String, Stack, Simulation
• 3951. Next Special Palindrome Number - HardTopics: Backtracking
• 2246. Maximum Employees to Be Invited to a Meeting - HardTopics: Depth-First Search, Graph, Topological Sort
• 3430. Count Days Without Meetings - MediumTopics: Array, Sorting
• 1699. Number of Ways Where Square of Number Is Equal to Product of Two Numbers - MediumTopics: Array, Hash Table, Math, Two Pointers
• 1512. Design Underground System - MediumTopics: Hash Table, String, Design
• 2520. Using a Robot to Print the Lexicographically Smallest String - MediumTopics: Hash Table, String, Stack, Greedy
• 2076. Sum of Digits of String After Convert - EasyTopics: String, Simulation
• 3406. Find All Possible Stable Binary Arrays I - MediumTopics: Dynamic Programming, Prefix Sum
• 636. Exclusive Time of Functions - MediumTopics: Array, Stack
• 2417. The Latest Time to Catch a Bus - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 2542. Average Value of Even Numbers That Are Divisible by Three - EasyTopics: Array, Math
• 3207. Make Three Strings Equal - EasyTopics: String
• 2628. Minimize the Maximum of Two Arrays - MediumTopics: Math, Binary Search, Number Theory
• 1270. Dinner Plate Stacks - HardTopics: Hash Table, Stack, Design, Heap (Priority Queue)
• 2127. Employees Whose Manager Left the Company - EasyTopics: Database
• 1020. Longest Turbulent Subarray - MediumTopics: Array, Dynamic Programming, Sliding Window
• 1295. Minimum Garden Perimeter to Collect Enough Apples - MediumTopics: Math, Binary Search
• 2293. Minimum Number of Steps to Make Two Strings Anagram II - MediumTopics: Hash Table, String, Counting
• 2002. Stone Game VIII - HardTopics: Array, Math, Dynamic Programming, Prefix Sum, Game Theory
• 1721. Maximum Profit of Operating a Centennial Wheel - MediumTopics: Array, Simulation
• 2704. Maximum Difference by Remapping a Digit - EasyTopics: Math, Greedy
• 3762. Maximize the Minimum Game Score - HardTopics: Array, Binary Search, Greedy
• 3904. Minimum Adjacent Swaps to Alternate Parity - MediumTopics: Array, Greedy
• 3866. Minimum Steps to Convert String with Operations - HardTopics: String, Dynamic Programming, Greedy
• 3875. Maximum Good Subtree Score - HardTopics: Array, Dynamic Programming, Bit Manipulation, Tree, Depth-First Search, Bitmask
• 3645. Maximize the Number of Target Nodes After Connecting Trees II - HardTopics: Tree, Depth-First Search, Breadth-First Search
• 2347. Count Nodes Equal to Average of Subtree - MediumTopics: Tree, Depth-First Search, Binary Tree
• 2921. Count Stepping Numbers in Range - HardTopics: String, Dynamic Programming
• 3835. Count Partitions With Max-Min Difference at Most K - MediumTopics: Array, Dynamic Programming, Queue, Sliding Window, Prefix Sum, Monotonic Queue
• 2337. Remove Digit From Number to Maximize Result - EasyTopics: String, Greedy, Enumeration
• 2625. Increment Submatrices by One - MediumTopics: Array, Matrix, Prefix Sum
• 2955. Account Balance After Rounded Purchase - EasyTopics: Math
• 901. Advantage Shuffle - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 1788. Stone Game VI - MediumTopics: Array, Math, Greedy, Sorting, Heap (Priority Queue), Game Theory
• 2701. Subsequence With the Minimum Score - HardTopics: Two Pointers, String, Binary Search
• 832. Binary Tree Pruning - MediumTopics: Tree, Depth-First Search, Binary Tree
• 594. Longest Harmonious Subsequence - EasyTopics: Array, Hash Table, Sliding Window, Sorting, Counting
• 3360. Minimum Deletions to Make String K-Special - MediumTopics: Hash Table, String, Greedy, Sorting, Counting
• 896. Smallest Subtree with all the Deepest Nodes - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3199. Distribute Candies Among Children I - EasyTopics: Math, Combinatorics, Enumeration
• 3927. Minimum Cost Path with Alternating Directions II - MediumTopics: Array, Dynamic Programming, Matrix
• 3884. Minimum Absolute Difference in Sliding Submatrix - MediumTopics: Array, Sorting, Matrix
• 3527. Alternating Groups III - HardTopics: Array, Binary Indexed Tree
• 2495. Number of Unique Subjects Taught by Each Teacher - EasyTopics: Database
• 2084. Maximum Number of Weeks for Which You Can Work - MediumTopics: Array, Greedy
• 2504. Find All Good Indices - MediumTopics: Array, Dynamic Programming, Prefix Sum
• 3683. Find the Lexicographically Largest String From the Box I - MediumTopics: Two Pointers, String, Enumeration
• 2639. Separate the Digits in an Array - EasyTopics: Array, Simulation
• 2744. Memoize II - HardTopics:
• 2902. Max Pair Sum in an Array - EasyTopics: Array, Hash Table
• 2604. Minimum Operations to Make Array Equal II - MediumTopics: Array, Math, Greedy
• 1925. Count Nice Pairs in an Array - MediumTopics: Array, Hash Table, Math, Counting
• 1480. Movie Rating - MediumTopics: Database
• 3867. Lexicographically Smallest String After Adjacent Removals - HardTopics: String, Dynamic Programming
• 3107. Maximum Spending After Buying Items - HardTopics: Array, Greedy, Sorting, Heap (Priority Queue), Matrix
• 1783. Ways to Make a Fair Array - MediumTopics: Array, Prefix Sum
• 3541. Report Spam Message - MediumTopics: Array, Hash Table, String
• 2164. Two Best Non-Overlapping Events - MediumTopics: Array, Binary Search, Dynamic Programming, Sorting, Heap (Priority Queue)
• 1563. Maximum Number of Darts Inside of a Circular Dartboard - HardTopics: Array, Math, Geometry
• 368. Largest Divisible Subset - MediumTopics: Array, Math, Dynamic Programming, Sorting
• 1463. The K Weakest Rows in a Matrix - EasyTopics: Array, Binary Search, Sorting, Heap (Priority Queue), Matrix
• 3212. Count the Number of Good Partitions - HardTopics: Array, Hash Table, Math, Combinatorics
• 1449. Print Words Vertically - MediumTopics: Array, String, Simulation
• 1553. Count Triplets That Can Form Two Arrays of Equal XOR - MediumTopics: Array, Hash Table, Math, Bit Manipulation, Prefix Sum
• 1662. Minimum Numbers of Function Calls to Make Target Array - MediumTopics: Array, Greedy, Bit Manipulation
• 1047. Maximize Sum Of Array After K Negations - EasyTopics: Array, Greedy, Sorting
• 3246. Check if Bitwise OR Has Trailing Zeros - EasyTopics: Array, Bit Manipulation
• 2342. Minimum Average Difference - MediumTopics: Array, Prefix Sum
• 1332. Count Vowels Permutation - HardTopics: Dynamic Programming
• 1218. Lowest Common Ancestor of Deepest Leaves - MediumTopics: Hash Table, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3842. Number of Ways to Assign Edge Weights II - HardTopics: Array, Math, Dynamic Programming, Tree, Depth-First Search
• 1858. Latest Time by Replacing Hidden Digits - EasyTopics: String, Greedy
• 3622. Maximum Frequency of an Element After Performing Operations I - MediumTopics: Array, Binary Search, Sliding Window, Sorting, Prefix Sum
• 432. All O`one Data Structure - HardTopics: Hash Table, Linked List, Design, Doubly-Linked List
• 805. Escape The Ghosts - MediumTopics: Array, Math
• 563. Binary Tree Tilt - EasyTopics: Tree, Depth-First Search, Binary Tree
• 3431. Find the Minimum Cost Array Permutation - HardTopics: Array, Dynamic Programming, Bit Manipulation, Bitmask
• 3682. Count the Number of Arrays with K Matching Adjacent Elements - HardTopics: Math, Combinatorics
• 3713. Frequencies of Shortest Supersequences - HardTopics: Array, String, Bit Manipulation, Graph, Topological Sort, Enumeration
• 1691. Minimum Number of Days to Disconnect Island - HardTopics: Array, Depth-First Search, Breadth-First Search, Matrix, Strongly Connected Component
• 515. Find Largest Value in Each Tree Row - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 1942. Primary Department for Each Employee - EasyTopics: Database
• 1268. Market Analysis I - MediumTopics: Database
• 3588. Count The Number of Winning Sequences - HardTopics: String, Dynamic Programming
• 2891. Maximum Beauty of an Array After Applying Operation - MediumTopics: Array, Binary Search, Sliding Window, Sorting
• 3755. Maximum Product of First and Last Elements of a Subsequence - MediumTopics: Array, Two Pointers
• 3219. Make Lexicographically Smallest Array by Swapping Elements - MediumTopics: Array, Union Find, Sorting
• 1227. Number of Equivalent Domino Pairs - EasyTopics: Array, Hash Table, Counting
• 2280. Count Good Triplets in an Array - HardTopics: Array, Binary Search, Divide and Conquer, Binary Indexed Tree, Segment Tree, Merge Sort, Ordered Set
• 3761. Maximum Difference Between Even and Odd Frequency II - HardTopics: String, Sliding Window, Enumeration, Prefix Sum
• 2561. Number of Distinct Averages - EasyTopics: Array, Hash Table, Two Pointers, Sorting
• 3165. Find Indices With Index and Value Difference I - EasyTopics: Array, Two Pointers
• 2394. Count Subarrays With Score Less Than K - HardTopics: Array, Binary Search, Sliding Window, Prefix Sum
• 1072. Next Greater Node In Linked List - MediumTopics: Array, Linked List, Stack, Monotonic Stack
• 3617. Find the Original Typed String I - EasyTopics: String
• 2792. Neighboring Bitwise XOR - MediumTopics: Array, Bit Manipulation
• 3356. Shortest Uncommon Substring in an Array - MediumTopics: Array, Hash Table, String, Trie
• 2329. Maximum Product After K Increments - MediumTopics: Array, Greedy, Heap (Priority Queue)
• 3034. Points That Intersect With Cars - EasyTopics: Array, Hash Table, Prefix Sum
• 980. Find the Shortest Superstring - HardTopics: Array, String, Dynamic Programming, Bit Manipulation, Bitmask
• 2571. Find the Pivot Integer - EasyTopics: Math, Prefix Sum
• 1682. Most Visited Sector in a Circular Track - EasyTopics: Array, Simulation
• 2836. Neither Minimum nor Maximum - EasyTopics: Array, Sorting
• 3390. Minimum Rectangles to Cover Points - MediumTopics: Array, Greedy, Sorting
• 3618. Find the Original Typed String II - HardTopics: String, Dynamic Programming, Prefix Sum
• 2139. Detect Squares - MediumTopics: Array, Hash Table, Design, Counting
• 3813. Smallest Palindromic Rearrangement II - HardTopics: Hash Table, Math, String, Combinatorics, Counting
• 2710. Minimum Operations to Reduce an Integer to 0 - MediumTopics: Dynamic Programming, Greedy, Bit Manipulation
• 2803. Modify Graph Edge Weights - HardTopics: Graph, Heap (Priority Queue), Shortest Path
• 1286. Constrained Subsequence Sum - HardTopics: Array, Dynamic Programming, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue
• 3754. Maximum Manhattan Distance After K Changes - MediumTopics: Hash Table, Math, String, Counting
• 2413. Smallest Number in Infinite Set - MediumTopics: Hash Table, Design, Heap (Priority Queue), Ordered Set
• 2709. Count the Number of Square-Free Subsets - MediumTopics: Array, Math, Dynamic Programming, Bit Manipulation, Bitmask
• 2557. Number of Subarrays With LCM Equal to K - MediumTopics: Array, Math, Number Theory
• 2904. Sorting Three Groups - MediumTopics: Array, Binary Search, Dynamic Programming
• 3753. Maximum Difference Between Even and Odd Frequency I - EasyTopics: Hash Table, String, Counting
• 2809. Create Hello World Function - EasyTopics:
• 508. Most Frequent Subtree Sum - MediumTopics: Hash Table, Tree, Depth-First Search, Binary Tree
• 3141. Minimum Size Subarray in Infinite Array - MediumTopics: Array, Hash Table, Sliding Window, Prefix Sum
• 3932. Find COVID Recovery Patients - MediumTopics: Database
• 1873. Longest Nice Substring - EasyTopics: Hash Table, String, Divide and Conquer, Bit Manipulation, Sliding Window
• 2415. Count the Number of Ideal Arrays - HardTopics: Math, Dynamic Programming, Combinatorics, Number Theory
• 1195. Distribute Candies to People - EasyTopics: Math, Simulation
• 2887. Sort Vowels in a String - MediumTopics: String, Sorting
• 1532. Reformat The String - EasyTopics: String
• 3534. Count Almost Equal Pairs I - MediumTopics: Array, Hash Table, Sorting, Counting, Enumeration
• 2884. Length of the Longest Valid Substring - HardTopics: Array, Hash Table, String, Sliding Window
• 1502. Construct K Palindrome Strings - MediumTopics: Hash Table, String, Greedy, Counting
• 3893. Generate Tag for Video Caption - EasyTopics: String, Simulation
• 3837. Grid Teleportation Traversal - MediumTopics: Array, Hash Table, Breadth-First Search, Matrix
• 3515. Find if Digit Game Can Be Won - EasyTopics: Array, Math
• 1638. Best Position for a Service Centre - HardTopics: Array, Math, Geometry, Randomized
• 3864. Count the Number of Computer Unlocking Permutations - MediumTopics: Array, Math, Brainteaser, Combinatorics
• 1692. Number of Ways to Reorder Array to Get Same BST - HardTopics: Array, Math, Divide and Conquer, Dynamic Programming, Tree, Union Find, Binary Search Tree, Memoization, Combinatorics, Binary Tree
• 3725. Maximum and Minimum Sums of at Most Size K Subarrays - HardTopics: Array, Math, Stack, Monotonic Stack
• 2846. Robot Collisions - HardTopics: Array, Stack, Sorting, Simulation
• 3311. Ant on the Boundary - EasyTopics: Array, Simulation, Prefix Sum
• 3860. Resulting String After Adjacent Removals - MediumTopics: String, Stack, Simulation
• 1337. Design Skiplist - HardTopics: Linked List, Design
• 3747. Maximum Difference Between Adjacent Elements in a Circular Array - EasyTopics: Array
• 3922. Minimum Moves to Reach Target in Grid - HardTopics: Math
• 2827. Greatest Common Divisor Traversal - HardTopics: Array, Math, Union Find, Number Theory
• 1674. Minimum Operations to Make Array Equal - MediumTopics: Math
• 3514. Shortest Distance After Road Addition Queries II - HardTopics: Array, Greedy, Graph, Ordered Set
• 2434. Design a Number Container System - MediumTopics: Hash Table, Design, Heap (Priority Queue), Ordered Set
• 3914. Check if Any Element Has Prime Frequency - EasyTopics: Array, Hash Table, Math, Counting, Number Theory
• 3171. Minimum Equal Sum of Two Arrays After Replacing Zeros - MediumTopics: Array, Greedy
• 3844. Number of Ways to Assign Edge Weights I - MediumTopics: Math, Tree, Depth-First Search
• 3190. Minimum Operations to Maximize Last Elements in Arrays - MediumTopics: Array, Enumeration
• 1988. Minimize Maximum Pair Sum in Array - MediumTopics: Array, Two Pointers, Greedy, Sorting
• 2351. Number of Ways to Buy Pens and Pencils - MediumTopics: Math, Enumeration
• 991. Array of Doubled Pairs - MediumTopics: Array, Hash Table, Greedy, Sorting
• 2423. Minimum Deletions to Make Array Divisible - HardTopics: Array, Math, Sorting, Heap (Priority Queue), Number Theory
• 2132. Convert 1D Array Into 2D Array - EasyTopics: Array, Matrix, Simulation
• 1398. Number of Ways to Stay in the Same Place After Some Steps - HardTopics: Dynamic Programming
• 1722. Throne Inheritance - MediumTopics: Hash Table, Tree, Depth-First Search, Design
• 1961. Maximum Ice Cream Bars - MediumTopics: Array, Greedy, Sorting, Counting Sort
• 3894. Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values - MediumTopics: Array, Hash Table, Greedy, Sorting, Heap (Priority Queue)
• 779. Max Chunks To Make Sorted II - HardTopics: Array, Stack, Greedy, Sorting, Monotonic Stack
• 1831. Ways to Split Array Into Three Subarrays - MediumTopics: Array, Two Pointers, Binary Search, Prefix Sum
• 3239. Minimum Number of Operations to Make X and Y Equal - MediumTopics: Dynamic Programming, Breadth-First Search, Memoization
• 3535. Find the Count of Monotonic Pairs I - HardTopics: Array, Math, Dynamic Programming, Combinatorics, Prefix Sum
• 2290. Removing Minimum Number of Magic Beans - MediumTopics: Array, Greedy, Sorting, Enumeration, Prefix Sum
• 738. Monotone Increasing Digits - MediumTopics: Math, Greedy
• 1723. Maximum Number of Achievable Transfer Requests - HardTopics: Array, Backtracking, Bit Manipulation, Enumeration
• 827. Expressive Words - MediumTopics: Array, Two Pointers, String
• 3687. Longest Special Path - HardTopics: Array, Hash Table, Tree, Depth-First Search, Prefix Sum
• 3445. Lexicographically Minimum String After Removing Stars - MediumTopics: Hash Table, String, Stack, Greedy, Heap (Priority Queue)
• 1321. Get Equal Substrings Within Budget - MediumTopics: String, Binary Search, Sliding Window, Prefix Sum
• 2300. Construct String With Repeat Limit - MediumTopics: Hash Table, String, Greedy, Heap (Priority Queue), Counting
• 790. Global and Local Inversions - MediumTopics: Array, Math
• 2532. Remove Letter To Equalize Frequency - EasyTopics: Hash Table, String, Counting
• 2727. Number of Senior Citizens - EasyTopics: Array, String
• 3578. Construct 2D Grid Matching Graph Layout - HardTopics: Array, Hash Table, Graph, Matrix
• 1738. Maximal Network Rank - MediumTopics: Graph
• 3870. Minimum Moves to Clean the Classroom - MediumTopics: Array, Hash Table, Bit Manipulation, Breadth-First Search, Matrix
• 2174. Next Greater Numerically Balanced Number - MediumTopics: Hash Table, Math, Backtracking, Counting, Enumeration
• 517. Super Washing Machines - HardTopics: Array, Greedy
• 3845. Maximum Sum of Edge Values in a Graph - HardTopics: Math, Greedy, Graph
• 1243. Sum of Nodes with Even-Valued Grandparent - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3568. Find the Key of the Numbers - EasyTopics: Math
• 2010. Check if Word Equals Summation of Two Words - EasyTopics: String
• 2720. Minimize the Maximum Difference of Pairs - MediumTopics: Array, Binary Search, Dynamic Programming, Greedy, Sorting
• 1689. Detect Pattern of Length M Repeated K or More Times - EasyTopics: Array, Enumeration
• 2469. Longest Subsequence With Limited Sum - EasyTopics: Array, Binary Search, Greedy, Sorting, Prefix Sum
• 2801. Difference of Number of Distinct Values on Diagonals - MediumTopics: Array, Hash Table, Matrix
• 852. Friends Of Appropriate Ages - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 3569. Count of Substrings Containing Every Vowel and K Consonants II - MediumTopics: Hash Table, String, Sliding Window
• 780. Max Chunks To Make Sorted - MediumTopics: Array, Stack, Greedy, Sorting, Monotonic Stack
• 1138. Grumpy Bookstore Owner - MediumTopics: Array, Sliding Window
• 2585. Delete Greatest Value in Each Row - EasyTopics: Array, Sorting, Heap (Priority Queue), Matrix, Simulation
• 1296. Kth Ancestor of a Tree Node - HardTopics: Binary Search, Dynamic Programming, Tree, Depth-First Search, Breadth-First Search, Design
• 3857. Find Maximum Number of Non Intersecting Substrings - MediumTopics: Hash Table, String, Dynamic Programming, Greedy
• 1746. Largest Substring Between Two Equal Characters - EasyTopics: Hash Table, String
• 1362. Airplane Seat Assignment Probability - MediumTopics: Math, Dynamic Programming, Brainteaser, Probability and Statistics
• 3763. Separate Squares I - MediumTopics: Array, Binary Search
• 1693. Sum of All Odd Length Subarrays - EasyTopics: Array, Math, Prefix Sum
• 2330. Maximum Total Beauty of the Gardens - HardTopics: Array, Two Pointers, Binary Search, Greedy, Sorting, Enumeration, Prefix Sum
• 3840. Find X Value of Array II - HardTopics: Array, Math, Segment Tree
• 778. Reorganize String - MediumTopics: Hash Table, String, Greedy, Sorting, Heap (Priority Queue), Counting
• 1707. Check If String Is Transformable With Substring Sort Operations - HardTopics: String, Greedy, Sorting
• 1388. Greatest Sum Divisible by Three - MediumTopics: Array, Dynamic Programming, Greedy, Sorting
• 1676. Minimum Number of Days to Eat N Oranges - HardTopics: Dynamic Programming, Memoization
• 2878. Apply Operations to Make All Array Elements Equal to Zero - MediumTopics: Array, Prefix Sum
• 2051. Longest Common Subpath - HardTopics: Array, Binary Search, Rolling Hash, Suffix Array, Hash Function
• 3170. Find Indices With Index and Value Difference II - MediumTopics: Array, Two Pointers
• 1210. Mean of Array After Removing Some Elements - EasyTopics: Array, Sorting
• 3637. Count Number of Balanced Permutations - HardTopics: Math, String, Dynamic Programming, Combinatorics
• 2838. Sum of Matrix After Queries - MediumTopics: Array, Hash Table
• 3815. Sum of Largest Prime Substrings - MediumTopics: Hash Table, Math, String, Sorting, Number Theory
• 750. Contain Virus - HardTopics: Array, Depth-First Search, Breadth-First Search, Matrix, Simulation
• 2858. Join Two Arrays by ID - MediumTopics:
• 3566. Find the Sequence of Strings Appeared on the Screen - MediumTopics: String, Simulation
• 857. Positions of Large Groups - EasyTopics: String
• 1698. Replace All ?'s to Avoid Consecutive Repeating Characters - EasyTopics: String
• 3700. Subsequences with a Unique Middle Mode I - HardTopics: Array, Hash Table, Math, Combinatorics
• 1355. Minimum Deletions to Make Array Beautiful - MediumTopics: Array, Stack, Greedy
• 2325. Number of Ways to Select Buildings - MediumTopics: String, Dynamic Programming, Prefix Sum
• 668. Kth Smallest Number in Multiplication Table - HardTopics: Math, Binary Search
• 3482. Construct String with Minimum Cost - HardTopics: Array, String, Dynamic Programming, Suffix Array
• 2095. Minimum Number of Swaps to Make the String Balanced - MediumTopics: Two Pointers, String, Stack, Greedy
• 2320. Find All K-Distant Indices in an Array - EasyTopics: Array, Two Pointers
• 2977. Check if a String Is an Acronym of Words - EasyTopics: Array, String
• 1330. Longest Arithmetic Subsequence of Given Difference - MediumTopics: Array, Hash Table, Dynamic Programming
• 1629. Minimum Possible Integer After at Most K Adjacent Swaps On Digits - HardTopics: String, Greedy, Binary Indexed Tree, Segment Tree
• 1267. Remove Zero Sum Consecutive Nodes from Linked List - MediumTopics: Hash Table, Linked List
• 3896. Minimum Time to Transport All Individuals - HardTopics: Array, Dynamic Programming, Bit Manipulation, Graph, Heap (Priority Queue), Shortest Path, Bitmask
• 3558. Find a Safe Walk Through a Grid - MediumTopics: Array, Breadth-First Search, Graph, Heap (Priority Queue), Matrix, Shortest Path
• 986. Largest Time for Given Digits - MediumTopics: Array, String, Backtracking, Enumeration
• 2308. Divide Array Into Equal Pairs - EasyTopics: Array, Hash Table, Bit Manipulation, Counting
• 2649. Count Total Number of Colored Cells - MediumTopics: Math
• 3025. Minimum Operations to Form Subsequence With Target Sum - HardTopics: Array, Greedy, Bit Manipulation
• 3793. Longest Palindrome After Substring Concatenation I - MediumTopics: Two Pointers, String, Dynamic Programming, Enumeration
• 1963. Find XOR Sum of All Pairs Bitwise AND - HardTopics: Array, Math, Bit Manipulation
• 1325. Path with Maximum Probability - MediumTopics: Array, Graph, Heap (Priority Queue), Shortest Path
• 2668. Form Smallest Number From Two Digit Arrays - EasyTopics: Array, Hash Table, Enumeration
• 858. Masking Personal Information - MediumTopics: String
• 3943. Find Overbooked Employees - MediumTopics: Database
• 1666. Make The String Great - EasyTopics: String, Stack
• 2006. Find the Student that Will Replace the Chalk - MediumTopics: Array, Binary Search, Simulation, Prefix Sum
• 1187. Print FooBar Alternately - MediumTopics: Concurrency
• 1468. Check If N and Its Double Exist - EasyTopics: Array, Hash Table, Two Pointers, Binary Search, Sorting
• 1647. Can Convert String in K Moves - MediumTopics: Hash Table, String
• 3774. Check If Digits Are Equal in String After Operations II - HardTopics: Math, String, Combinatorics, Number Theory
• 2102. Find the Middle Index in Array - EasyTopics: Array, Prefix Sum
• 2714. Left and Right Sum Differences - EasyTopics: Array, Prefix Sum
• 1933. Number of Different Integers in a String - EasyTopics: Hash Table, String
• 914. Random Point in Non-overlapping Rectangles - MediumTopics: Array, Math, Binary Search, Reservoir Sampling, Prefix Sum, Ordered Set, Randomized
• 3610. Find X-Sum of All K-Long Subarrays I - EasyTopics: Array, Hash Table, Sliding Window, Heap (Priority Queue)
• 3519. Find the Number of Winning Players - EasyTopics: Array, Hash Table, Counting
• 2580. Circular Sentence - EasyTopics: String
• 477. Total Hamming Distance - MediumTopics: Array, Math, Bit Manipulation
• 1610. XOR Operation in an Array - EasyTopics: Math, Bit Manipulation
• 2855. Maximum Number of Jumps to Reach the Last Index - MediumTopics: Array, Dynamic Programming
• 3956. Trionic Array II - HardTopics: Array, Dynamic Programming
• 2775. Generate Fibonacci Sequence - EasyTopics:
• 3843. Partition Array into Two Equal Product Subsets - MediumTopics: Array, Bit Manipulation, Recursion, Enumeration
• 1464. Reduce Array Size to The Half - MediumTopics: Array, Hash Table, Greedy, Sorting, Heap (Priority Queue)
• 1087. Longest Arithmetic Subsequence - MediumTopics: Array, Hash Table, Binary Search, Dynamic Programming
• 808. Number of Matching Subsequences - MediumTopics: Array, Hash Table, String, Binary Search, Dynamic Programming, Trie, Sorting
• 1277. Largest Multiple of Three - HardTopics: Array, Math, Dynamic Programming, Greedy, Sorting
• 1740. Count Subtrees With Max Distance Between Cities - HardTopics: Dynamic Programming, Bit Manipulation, Tree, Enumeration, Bitmask
• 3312. Number of Changing Keys - EasyTopics: String
• 1470. Tweet Counts Per Frequency - MediumTopics: Hash Table, Binary Search, Design, Sorting, Ordered Set
• 318. Maximum Product of Word Lengths - MediumTopics: Array, String, Bit Manipulation
• 2129. Number of Pairs of Interchangeable Rectangles - MediumTopics: Array, Hash Table, Math, Counting, Number Theory
• 993. Tallest Billboard - HardTopics: Array, Dynamic Programming
• 3826. Maximum Profit from Valid Topological Order in DAG - HardTopics: Array, Dynamic Programming, Bit Manipulation, Graph, Topological Sort, Bitmask
• 3954. Maximum Balanced Shipments - MediumTopics: Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
• 495. Teemo Attacking - EasyTopics: Array, Simulation
• 2266. Minimum Cost to Set Cooking Time - MediumTopics: Math, Enumeration
• 2008. Minimum Cost to Change the Final Value of Expression - HardTopics: Math, String, Dynamic Programming, Stack
• 3782. Find Valid Emails - EasyTopics: Database
• 2760. Snail Traversal - MediumTopics:
• 2471. Minimum Amount of Time to Collect Garbage - MediumTopics: Array, String, Prefix Sum
• 3202. High-Access Employees - MediumTopics: Array, Hash Table, String, Sorting
• 675. Cut Off Trees for Golf Event - HardTopics: Array, Breadth-First Search, Heap (Priority Queue), Matrix
• 1264. Maximum Number of Words You Can Type - EasyTopics: Hash Table, String
• 441. Arranging Coins - EasyTopics: Math, Binary Search
• 1041. Available Captures for Rook - EasyTopics: Array, Matrix, Simulation
• 3477. Minimum Operations to Make Binary Array Elements Equal to One II - MediumTopics: Array, Dynamic Programming, Greedy
• 2366. Maximum Bags With Full Capacity of Rocks - MediumTopics: Array, Greedy, Sorting
• 2553. Total Cost to Hire K Workers - MediumTopics: Array, Two Pointers, Heap (Priority Queue), Simulation
• 1386. Shift 2D Grid - EasyTopics: Array, Matrix, Simulation
• 2338. Minimum Consecutive Cards to Pick Up - MediumTopics: Array, Hash Table, Sliding Window
• 3367. Find the Sum of Encrypted Integers - EasyTopics: Array, Math
• 2530. Minimize Maximum of Array - MediumTopics: Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum
• 1354. Find Players With Zero or One Losses - MediumTopics: Array, Hash Table, Sorting, Counting
• 1450. Delete Leaves With a Given Value - MediumTopics: Tree, Depth-First Search, Binary Tree
• 1070. Convert to Base -2 - MediumTopics: Math
• 3732. Calculate Score After Performing Instructions - MediumTopics: Array, Hash Table, String, Simulation
• 1850. Minimum Length of String After Deleting Similar Ends - MediumTopics: Two Pointers, String
• 345. Reverse Vowels of a String - EasyTopics: Two Pointers, String
• 2505. Number of Good Paths - HardTopics: Array, Hash Table, Tree, Union Find, Graph, Sorting
• 2645. Pass the Pillow - EasyTopics: Math, Simulation
• 1260. Day of the Year - EasyTopics: Math, String
• 2398. Check if Matrix Is X-Matrix - EasyTopics: Array, Matrix
• 926. Find and Replace Pattern - MediumTopics: Array, Hash Table, String
• 1996. Number of Ways to Rearrange Sticks With K Sticks Visible - HardTopics: Math, Dynamic Programming, Combinatorics
• 3328. Apply Operations to Make Sum of Array Greater Than or Equal to k - MediumTopics: Math, Greedy, Enumeration
• 2243. Check if All A's Appears Before All B's - EasyTopics: String
• 1443. Minimum Distance to Type a Word Using Two Fingers - HardTopics: String, Dynamic Programming
• 1787. Sum of Absolute Differences in a Sorted Array - MediumTopics: Array, Math, Prefix Sum
• 1231. Replace Elements with Greatest Element on Right Side - EasyTopics: Array
• 796. Reaching Points - HardTopics: Math
• 3829. Shortest Path in a Weighted Tree - HardTopics: Array, Tree, Depth-First Search, Binary Indexed Tree, Segment Tree
• 1394. Minimum Path Cost in a Grid - MediumTopics: Array, Dynamic Programming, Matrix
• 1474. Longest ZigZag Path in a Binary Tree - MediumTopics: Dynamic Programming, Tree, Depth-First Search, Binary Tree
• 1882. The Number of Employees Which Report to Each Employee - EasyTopics: Database
• 799. Minimum Distance Between BST Nodes - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Tree
• 598. Range Addition II - EasyTopics: Array, Math
• 3828. Analyze Organization Hierarchy - HardTopics: Database
• 1659. Get the Maximum Score - HardTopics: Array, Two Pointers, Dynamic Programming, Greedy
• 1381. Maximum Score Words Formed by Letters - HardTopics: Array, String, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 1527. Number of Ways to Paint N × 3 Grid - HardTopics: Dynamic Programming
• 3151. Minimum Processing Time - MediumTopics: Array, Greedy, Sorting
• 1003. Minimum Area Rectangle II - MediumTopics: Array, Hash Table, Math, Geometry
• 3832. Minimum Cost to Reach Every Position - EasyTopics: Array
• 3518. Maximum Multiplication Score - MediumTopics: Array, Dynamic Programming
• 3142. Longest Unequal Adjacent Groups Subsequence II - MediumTopics: Array, String, Dynamic Programming
• 1664. Find Users With Valid E-Mails - EasyTopics: Database
• 717. 1-bit and 2-bit Characters - EasyTopics: Array
• 1261. Swap For Longest Repeated Character Substring - MediumTopics: Hash Table, String, Sliding Window
• 677. Map Sum Pairs - MediumTopics: Hash Table, String, Design, Trie
• 1062. Partition Array Into Three Parts With Equal Sum - EasyTopics: Array, Greedy
• 2787. Movement of Robots - MediumTopics: Array, Brainteaser, Sorting, Prefix Sum
• 3810. Count Numbers with Non-Decreasing Digits - HardTopics: Math, String, Dynamic Programming
• 1422. Divide Array in Sets of K Consecutive Numbers - MediumTopics: Array, Hash Table, Greedy, Sorting
• 1168. Duplicate Zeros - EasyTopics: Array, Two Pointers
• 3017. Number of Beautiful Integers in the Range - HardTopics: Math, Dynamic Programming
• 1232. Sum of Mutated Array Closest to Target - MediumTopics: Array, Binary Search, Sorting
• 2327. Largest Number After Digit Swaps by Parity - EasyTopics: Sorting, Heap (Priority Queue)
• 3468. Find the Encrypted String - EasyTopics: String
• 2594. Count Pairs Of Similar Strings - EasyTopics: Array, Hash Table, String, Bit Manipulation, Counting
• 2270. Find All Lonely Numbers in the Array - MediumTopics: Array, Hash Table, Counting
• 3648. Find the Maximum Number of Fruits Collected - HardTopics: Array, Dynamic Programming, Matrix
• 2016. Reduction Operations to Make the Array Elements Equal - MediumTopics: Array, Sorting
• 2581. Divide Players Into Teams of Equal Skill - MediumTopics: Array, Hash Table, Two Pointers, Sorting
• 2624. Difference Between Element Sum and Digit Sum of an Array - EasyTopics: Array, Math
• 3408. Count the Number of Special Characters I - EasyTopics: Hash Table, String
• 1156. Occurrences After Bigram - EasyTopics: String
• 2059. Unique Length-3 Palindromic Subsequences - MediumTopics: Hash Table, String, Bit Manipulation, Prefix Sum
• 1704. Special Positions in a Binary Matrix - EasyTopics: Array, Matrix
• 2487. Optimal Partition of String - MediumTopics: Hash Table, String, Greedy
• 2529. Range Product Queries of Powers - MediumTopics: Array, Bit Manipulation, Prefix Sum
• 2689. Rearranging Fruits - HardTopics: Array, Hash Table, Greedy, Sort
• 867. New 21 Game - MediumTopics: Math, Dynamic Programming, Sliding Window, Probability and Statistics
• 3567. Convert Date to Binary - EasyTopics: Math, String
• 1524. String Matching in an Array - EasyTopics: Array, String, String Matching
• 1294. Range Frequency Queries - MediumTopics: Array, Hash Table, Binary Search, Design, Segment Tree
• 2155. Find Missing Observations - MediumTopics: Array, Math, Simulation
• 1500. Count Largest Group - EasyTopics: Hash Table, Math
• 1571. Allocate Mailboxes - HardTopics: Array, Math, Dynamic Programming, Sorting
• 3276. Minimum Number of Pushes to Type Word II - MediumTopics: Hash Table, String, Greedy, Sorting, Counting
• 2053. Check if All Characters Have Equal Number of Occurrences - EasyTopics: Hash Table, String, Counting
• 1306. Minimum Absolute Difference - EasyTopics: Array, Sorting
• 2191. Minimum Number of Food Buckets to Feed the Hamsters - MediumTopics: String, Dynamic Programming, Greedy
• 1479. Construct Target Array With Multiple Sums - HardTopics: Array, Heap (Priority Queue)
• 2820. Return Length of Arguments Passed - EasyTopics:
• 2187. Vowels of All Substrings - MediumTopics: Math, String, Dynamic Programming, Combinatorics
• 933. Increasing Order Search Tree - EasyTopics: Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 3140. Count Visited Nodes in a Directed Graph - HardTopics: Dynamic Programming, Graph, Memoization
• 1489. Pizza With 3n Slices - HardTopics: Array, Dynamic Programming, Greedy, Heap (Priority Queue)
• 3878. Maximize Count of Distinct Primes After Split - HardTopics: Array, Math, Segment Tree, Number Theory
• 1994. Minimum Number of Swaps to Make the Binary String Alternating - MediumTopics: String, Greedy
• 3902. Maximize Spanning Tree Stability with Upgrades - HardTopics: Binary Search, Greedy, Union Find, Graph, Minimum Spanning Tree
• 3509. K-th Largest Perfect Subtree Size in Binary Tree - MediumTopics: Tree, Depth-First Search, Sorting, Binary Tree
• 2274. Keep Multiplying Found Values by Two - EasyTopics: Array, Hash Table, Sorting, Simulation
• 1801. Average Time of Process per Machine - EasyTopics: Database
• 1644. Maximum Number of Non-Overlapping Substrings - HardTopics: String, Greedy
• 2377. Check if Number Has Equal Digit Count and Digit Value - EasyTopics: Hash Table, String, Counting
• 2160. Minimum Operations to Make a Uni-Value Grid - MediumTopics: Array, Math, Sorting, Matrix
• 3800. Longest Common Prefix Between Adjacent Strings After Removals - MediumTopics: Array, String
• 3739. Manhattan Distances of All Arrangements of Pieces - HardTopics: Math, Combinatorics
• 1136. Actors and Directors Who Cooperated At Least Three Times - EasyTopics: Database
• 823. Split Array With Same Average - HardTopics: Array, Math, Dynamic Programming, Bit Manipulation, Bitmask
• 3068. Rename Columns - EasyTopics:
• 313. Super Ugly Number - MediumTopics: Array, Math, Dynamic Programming
• 564. Find the Closest Palindrome - HardTopics: Math, String
• 372. Super Pow - MediumTopics: Math, Divide and Conquer
• 3348. Minimum Cost Walk in Weighted Graph - HardTopics: Array, Bit Manipulation, Union Find, Graph
• 1475. Maximum Sum BST in Binary Tree - HardTopics: Dynamic Programming, Tree, Depth-First Search, Binary Search Tree, Binary Tree
• 458. Poor Pigs - HardTopics: Math, Dynamic Programming, Combinatorics
• 3553. Check if Two Chessboard Squares Have the Same Color - EasyTopics: Math, String
• 2042. Maximum Product Difference Between Two Pairs - EasyTopics: Array, Sorting
• 3046. Minimum Operations to Make a Special Number - MediumTopics: Math, String, Greedy, Enumeration
• 3079. Minimum Edge Weight Equilibrium Queries in a Tree - HardTopics: Array, Tree, Graph, Strongly Connected Component
• 3095. Maximum Number of Alloys - MediumTopics: Array, Binary Search
• 3643. Zero Array Transformation II - MediumTopics: Array, Binary Search, Prefix Sum
• 2696. The Number of Beautiful Subsets - MediumTopics: Array, Hash Table, Math, Dynamic Programming, Backtracking, Sorting, Combinatorics
• 593. Valid Square - MediumTopics: Math, Geometry
• 2684. Determine the Winner of a Bowling Game - EasyTopics: Array, Simulation
• 2749. Promise Time Limit - MediumTopics:
• 3485. Maximize Score of Numbers in Ranges - MediumTopics: Array, Binary Search, Greedy, Sorting
• 2093. Check If String Is a Prefix of Array - EasyTopics: Array, Two Pointers, String
• 2652. Count Number of Possible Root Nodes - HardTopics: Array, Hash Table, Dynamic Programming, Tree, Depth-First Search
• 2692. Take Gifts From the Richest Pile - EasyTopics: Array, Heap (Priority Queue), Simulation
• 3092. Minimum Moves to Spread Stones Over Grid - MediumTopics: Array, Dynamic Programming, Breadth-First Search, Matrix
• 3955. Threshold Majority Queries - HardTopics: Array, Hash Table, Binary Search, Divide and Conquer, Counting, Prefix Sum
• 1975. Minimum Distance to the Target Element - EasyTopics: Array
• 2365. Percentage of Letter in String - EasyTopics: String
• 2538. Minimum Cost to Make Array Equal - HardTopics: Array, Binary Search, Greedy, Sorting, Prefix Sum
• 3570. Count of Substrings Containing Every Vowel and K Consonants I - MediumTopics: Hash Table, String, Sliding Window
• 886. Score of Parentheses - MediumTopics: String, Stack
• 1148. Adding Two Negabinary Numbers - MediumTopics: Array, Math
• 2427. First Letter to Appear Twice - EasyTopics: Hash Table, String, Bit Manipulation, Counting
• 1989. Minimum XOR Sum of Two Arrays - HardTopics: Array, Dynamic Programming, Bit Manipulation, Bitmask
• 2507. Number of Common Factors - EasyTopics: Math, Enumeration, Number Theory
• 1045. Check If Word Is Valid After Substitutions - MediumTopics: String, Stack
• 959. 3Sum With Multiplicity - MediumTopics: Array, Hash Table, Two Pointers, Sorting, Counting
• 3528. Reach End of Array With Max Score - MediumTopics: Array, Greedy
• 693. Binary Number with Alternating Bits - EasyTopics: Bit Manipulation
• 2747. Apply Transform Over Each Element in Array - EasyTopics:
• 2115. Number of Unique Good Subsequences - HardTopics: String, Dynamic Programming
• 1395. Minimum Time Visiting All Points - EasyTopics: Array, Math, Geometry
• 599. Minimum Index Sum of Two Lists - EasyTopics: Array, Hash Table, String
• 3332. Minimum Operations to Exceed Threshold Value II - MediumTopics: Array, Heap (Priority Queue), Simulation
• 3223. Count Complete Substrings - HardTopics: Hash Table, String, Sliding Window
• 2620. Find Consecutive Integers from a Data Stream - MediumTopics: Hash Table, Design, Queue, Counting, Data Stream
• 938. Numbers At Most N Given Digit Set - HardTopics: Array, Math, String, Binary Search, Dynamic Programming
• 2358. Number of Ways to Split Array - MediumTopics: Array, Prefix Sum
• 3766. Maximum Median Sum of Subsequences of Size 3 - MediumTopics: Array, Math, Greedy, Sorting, Game Theory
• 2380. Booking Concert Tickets in Groups - HardTopics: Binary Search, Design, Binary Indexed Tree, Segment Tree
• 1967. Longest Substring Of All Vowels in Order - MediumTopics: String, Sliding Window
• 2017. Minimum Number of Flips to Make the Binary String Alternating - MediumTopics: String, Dynamic Programming, Sliding Window
• 2055. Describe the Painting - MediumTopics: Array, Hash Table, Sorting, Prefix Sum
• 462. Minimum Moves to Equal Array Elements II - MediumTopics: Array, Math, Sorting
• 1361. Tiling a Rectangle with the Fewest Squares - HardTopics: Backtracking
• 3439. Find Minimum Diameter After Merging Two Trees - HardTopics: Tree, Depth-First Search, Breadth-First Search, Graph
• 1649. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target - MediumTopics: Array, Hash Table, Greedy, Prefix Sum
• 284. Peeking Iterator - MediumTopics: Array, Design, Iterator
• 1652. Minimum Suffix Flips - MediumTopics: String, Greedy
• 1896. Maximum Score from Performing Multiplication Operations - HardTopics: Array, Dynamic Programming
• 1423. Maximum Number of Occurrences of a Substring - MediumTopics: Hash Table, String, Sliding Window
• 872. Split Array into Fibonacci Sequence - MediumTopics: String, Backtracking
• 2388. Replace Elements in an Array - MediumTopics: Array, Hash Table, Simulation
• 3331. Minimum Operations to Exceed Threshold Value I - EasyTopics: Array
• 1701. Remove Max Number of Edges to Keep Graph Fully Traversable - HardTopics: Union Find, Graph
• 2722. Prime In Diagonal - EasyTopics: Array, Math, Matrix, Number Theory
• 482. License Key Formatting - EasyTopics: String
• 2277. Count Equal and Divisible Pairs in an Array - EasyTopics: Array
• 3865. Find Product Recommendation Pairs - MediumTopics: Database
• 2163. Kth Distinct String in an Array - EasyTopics: Array, Hash Table, String, Counting
• 3032. Maximize Value of Function in a Ball Passing Game - HardTopics: Array, Dynamic Programming, Bit Manipulation
• 3952. Trionic Array I - EasyTopics: Array
• 1487. Cinema Seat Allocation - MediumTopics: Array, Hash Table, Greedy, Bit Manipulation
• 1950. Sign of the Product of an Array - EasyTopics: Array, Math
• 3470. Maximum Score From Grid Operations - HardTopics: Array, Dynamic Programming, Matrix, Prefix Sum
• 2285. Design Bitset - MediumTopics: Array, Hash Table, String, Design
• 2028. The Earliest and Latest Rounds Where Players Compete - HardTopics: Dynamic Programming, Memoization
• 629. K Inverse Pairs Array - HardTopics: Dynamic Programming
• 1621. Number of Subsequences That Satisfy the Given Sum Condition - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 2275. Find Substring With Given Hash Value - HardTopics: String, Sliding Window, Rolling Hash, Hash Function
• 1577. Probability of a Two Boxes Having The Same Number of Distinct Balls - HardTopics: Array, Math, Dynamic Programming, Backtracking, Combinatorics, Probability and Statistics
• 839. Short Encoding of Words - MediumTopics: Array, Hash Table, String, Trie
• 2199. Two Furthest Houses With Different Colors - EasyTopics: Array, Greedy
• 3654. Minimum Array Sum - MediumTopics: Array, Dynamic Programming
• 3200. Number of Strings Which Can Be Rearranged to Contain Substring - MediumTopics: Math, Dynamic Programming, Combinatorics
• 843. Binary Trees With Factors - MediumTopics: Array, Hash Table, Dynamic Programming, Sorting
• 2525. Count Number of Distinct Integers After Reverse Operations - MediumTopics: Array, Hash Table, Math, Counting
• 475. Heaters - MediumTopics: Array, Two Pointers, Binary Search, Sorting
• 2478. Longest Nice Subarray - MediumTopics: Array, Bit Manipulation, Sliding Window
• 2564. Most Profitable Path in a Tree - MediumTopics: Array, Tree, Depth-First Search, Breadth-First Search, Graph
• 3235. Minimum Cost to Convert String I - MediumTopics: Array, String, Graph, Shortest Path
• 868. Push Dominoes - MediumTopics: Two Pointers, String, Dynamic Programming
• 1632. Number of Good Ways to Split a String - MediumTopics: Hash Table, String, Dynamic Programming, Bit Manipulation
• 2005. Check if All the Integers in a Range Are Covered - EasyTopics: Array, Hash Table, Prefix Sum
• 3831. Find X Value of Array I - MediumTopics: Array, Math, Dynamic Programming
• 3453. Generate Binary Strings Without Adjacent Zeros - MediumTopics: String, Backtracking, Bit Manipulation
• 2533. Bitwise XOR of All Pairings - MediumTopics: Array, Bit Manipulation, Brainteaser
• 652. Find Duplicate Subtrees - MediumTopics: Hash Table, Tree, Depth-First Search, Binary Tree
• 1895. Minimum Number of Operations to Move All Balls to Each Box - MediumTopics: Array, String, Prefix Sum
• 1002. Maximum Width Ramp - MediumTopics: Array, Two Pointers, Stack, Monotonic Stack
• 3490. Find the Maximum Length of Valid Subsequence I - MediumTopics: Array, Dynamic Programming
• 2631. Sort the Students by Their Kth Score - MediumTopics: Array, Sorting, Matrix
• 1491. Number of Times Binary String Is Prefix-Aligned - MediumTopics: Array
• 961. Long Pressed Name - EasyTopics: Two Pointers, String
• 2663. Distribute Money to Maximum Children - EasyTopics: Math, Greedy
• 3269. Number of Subarrays That Match a Pattern I - MediumTopics: Array, Rolling Hash, String Matching, Hash Function
• 1770. Minimum Deletions to Make Character Frequencies Unique - MediumTopics: Hash Table, String, Greedy, Sorting
• 2917. Count Pairs Whose Sum is Less than Target - EasyTopics: Array, Two Pointers, Binary Search, Sorting
• 2346. Largest 3-Same-Digit Number in String - EasyTopics: String
• 2568. Minimum Fuel Cost to Report to the Capital - MediumTopics: Tree, Depth-First Search, Breadth-First Search, Graph
• 3812. Smallest Palindromic Rearrangement I - MediumTopics: String, Sorting, Counting Sort
• 731. My Calendar II - MediumTopics: Array, Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set
• 2746. Filter Elements from Array - EasyTopics:
• 363. Max Sum of Rectangle No Larger Than K - HardTopics: Array, Binary Search, Matrix, Prefix Sum, Ordered Set
• 2379. Maximum Total Importance of Roads - MediumTopics: Greedy, Graph, Sorting, Heap (Priority Queue)
• 3789. Maximize Subarrays After Removing One Conflicting Pair - HardTopics: Array, Segment Tree, Enumeration, Prefix Sum
• 1073. Number of Enclaves - MediumTopics: Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
• 1037. Minimum Number of K Consecutive Bit Flips - HardTopics: Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum
• 728. Self Dividing Numbers - EasyTopics: Math
• 3112. Count Valid Paths in a Tree - HardTopics: Math, Dynamic Programming, Tree, Depth-First Search, Number Theory
• 3767. Find Students Who Improved - MediumTopics: Database
• 2100. Minimum Non-Zero Product of the Array Elements - MediumTopics: Math, Greedy, Recursion
• 1498. Find a Corresponding Node of a Binary Tree in a Clone of That Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 1514. Minimum Value to Get Positive Step by Step Sum - EasyTopics: Array, Prefix Sum
• 2333. Count Number of Rectangles Containing Each Point - MediumTopics: Array, Hash Table, Binary Search, Binary Indexed Tree, Sorting
• 500. Keyboard Row - EasyTopics: Array, Hash Table, String
• 1709. Alert Using Same Key-Card Three or More Times in a One Hour Period - MediumTopics: Array, Hash Table, String, Sorting
• 841. Shortest Distance to a Character - EasyTopics: Array, Two Pointers, String
• 3530. Odd and Even Transactions - MediumTopics: Database
• 1093. Recover a Tree From Preorder Traversal - HardTopics: String, Tree, Depth-First Search, Binary Tree
• 2587. Design Memory Allocator - MediumTopics: Array, Hash Table, Design, Simulation
• 2244. Number of Laser Beams in a Bank - MediumTopics: Array, Math, String, Matrix
• 413. Arithmetic Slices - MediumTopics: Array, Dynamic Programming, Sliding Window
• 3305. Count Prefix and Suffix Pairs II - HardTopics: Array, String, Trie, Rolling Hash, String Matching, Hash Function
• 1462. List the Products Ordered in a Period - EasyTopics: Database
• 2859. Add Two Promises - EasyTopics:
• 553. Optimal Division - MediumTopics: Array, Math, Dynamic Programming
• 1426. Find N Unique Integers Sum up to Zero - EasyTopics: Array, Math
• 382. Linked List Random Node - MediumTopics: Linked List, Math, Reservoir Sampling, Randomized
• 897. Prime Palindrome - MediumTopics: Math, Number Theory
• 2673. Maximize Win From Two Segments - MediumTopics: Array, Binary Search, Sliding Window
• 2168. Check if Numbers Are Ascending in a Sentence - EasyTopics: String
• 2257. Earliest Possible Day of Full Bloom - HardTopics: Array, Greedy, Sorting
• 2508. Maximum Sum of an Hourglass - MediumTopics: Array, Matrix, Prefix Sum
• 1048. Clumsy Factorial - MediumTopics: Math, Stack, Simulation
• 2375. Minimum Obstacle Removal to Reach Corner - HardTopics: Array, Breadth-First Search, Graph, Heap (Priority Queue), Matrix, Shortest Path
• 2728. Sum in a Matrix - MediumTopics: Array, Sorting, Heap (Priority Queue), Matrix, Simulation
• 2741. Function Composition - EasyTopics:
• 1818. Maximum Score From Removing Substrings - MediumTopics: String, Stack, Greedy
• 1542. Consecutive Characters - EasyTopics: String
• 2418. Minimum Sum of Squared Difference - MediumTopics: Array, Binary Search, Greedy, Sorting, Heap (Priority Queue)
• 828. Chalkboard XOR Game - HardTopics: Array, Math, Bit Manipulation, Brainteaser, Game Theory
• 1389. Minimum Moves to Move a Box to Their Target Location - HardTopics: Array, Breadth-First Search, Heap (Priority Queue), Matrix
• 730. Count Different Palindromic Subsequences - HardTopics: String, Dynamic Programming
• 2130. Maximum Product of the Length of Two Palindromic Subsequences - MediumTopics: String, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 2341. Count Prefixes of a Given String - EasyTopics: Array, String
• 2367. Minimum Lines to Represent a Line Chart - MediumTopics: Array, Math, Geometry, Sorting, Number Theory
• 1094. Matrix Cells in Distance Order - EasyTopics: Array, Math, Geometry, Sorting, Matrix
• 396. Rotate Function - MediumTopics: Array, Math, Dynamic Programming
• 1228. Minimum Cost Tree From Leaf Values - MediumTopics: Array, Dynamic Programming, Stack, Greedy, Monotonic Stack
• 2549. Next Greater Element IV - HardTopics: Array, Binary Search, Stack, Sorting, Heap (Priority Queue), Monotonic Stack
• 774. Maximum Depth of N-ary Tree - EasyTopics: Tree, Depth-First Search, Breadth-First Search
• 2998. Count Symmetric Integers - EasyTopics: Math, Enumeration
• 1685. Stone Game V - HardTopics: Array, Math, Dynamic Programming, Game Theory
• 2089. Maximum Matrix Sum - MediumTopics: Array, Greedy, Matrix
• 950. X of a Kind in a Deck of Cards - EasyTopics: Array, Hash Table, Math, Counting, Number Theory
• 561. Array Partition - EasyTopics: Array, Greedy, Sorting, Counting Sort
• 824. Number of Lines To Write String - EasyTopics: Array, String
• 2752. Sum Multiples - EasyTopics: Math
• 1844. Maximum Number of Balls in a Box - EasyTopics: Hash Table, Math, Counting
• 3822. Fill a Special Grid - MediumTopics: Array, Divide and Conquer, Matrix
• 1159. Smallest Subsequence of Distinct Characters - MediumTopics: String, Stack, Greedy, Monotonic Stack
• 2498. Smallest Subarrays With Maximum Bitwise OR - MediumTopics: Array, Binary Search, Bit Manipulation, Sliding Window
• 2359. Maximum White Tiles Covered by a Carpet - MediumTopics: Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum
• 1839. Decode XORed Array - EasyTopics: Array, Bit Manipulation
• 2321. Minimum Weighted Subgraph With the Required Paths - HardTopics: Graph, Shortest Path
• 2712. Find the Maximum Number of Marked Indices - MediumTopics: Array, Two Pointers, Binary Search, Greedy, Sorting
• 1256. Rank Transform of an Array - EasyTopics: Array, Hash Table, Sorting
• 2873. Prime Pairs With Target Sum - MediumTopics: Array, Math, Enumeration, Number Theory
• 2634. Minimum Common Value - EasyTopics: Array, Hash Table, Two Pointers, Binary Search
• 3629. Total Characters in String After Transformations I - MediumTopics: Hash Table, Math, String, Dynamic Programming, Counting
• 895. Shortest Path to Get All Keys - HardTopics: Array, Bit Manipulation, Breadth-First Search, Matrix
• 472. Concatenated Words - HardTopics: Array, String, Dynamic Programming, Depth-First Search, Trie, Sorting
• 1653. Number of Good Leaf Nodes Pairs - MediumTopics: Tree, Depth-First Search, Binary Tree
• 1510. Find Lucky Integer in an Array - EasyTopics: Array, Hash Table, Counting
• 1096. Maximum Sum of Two Non-Overlapping Subarrays - MediumTopics: Array, Dynamic Programming, Sliding Window
• 2824. Check if The Number is Fascinating - EasyTopics: Hash Table, Math
• 1875. Tree of Coprimes - HardTopics: Array, Math, Tree, Depth-First Search, Number Theory
• 1372. Check If It Is a Good Array - HardTopics: Array, Math, Number Theory
• 1331. Path with Maximum Gold - MediumTopics: Array, Backtracking, Matrix
• 3921. Find Consistently Improving Employees - MediumTopics: Database
• 3386. Find Edges in Shortest Paths - HardTopics: Depth-First Search, Breadth-First Search, Graph, Heap (Priority Queue), Shortest Path
• 2236. Maximum Twin Sum of a Linked List - MediumTopics: Linked List, Two Pointers, Stack
• 3372. Longest Strictly Increasing or Strictly Decreasing Subarray - EasyTopics: Array
• 1252. Break a Palindrome - MediumTopics: String, Greedy
• 1418. Fair Distribution of Cookies - MediumTopics: Array, Dynamic Programming, Backtracking, Bit Manipulation, Bitmask
• 2188. Minimized Maximum of Products Distributed to Any Store - MediumTopics: Array, Binary Search, Greedy
• 2400. Minimum Score After Removals on a Tree - HardTopics: Array, Bit Manipulation, Tree, Depth-First Search
• 2886. Faulty Keyboard - EasyTopics: String, Simulation
• 1133. Last Substring in Lexicographical Order - HardTopics: Two Pointers, String
• 974. Reorder Data in Log Files - MediumTopics: Array, String, Sorting
• 2240. Intervals Between Identical Elements - MediumTopics: Array, Hash Table, Prefix Sum
• 2288. Count Operations to Obtain Zero - EasyTopics: Math, Simulation
• 3415. Check if Grid Satisfies Conditions - EasyTopics: Array, Matrix
• 2610. Closest Prime Numbers in Range - MediumTopics: Math, Number Theory
• 1999. Longer Contiguous Segments of Ones than Zeros - EasyTopics: String
• 2228. Watering Plants II - MediumTopics: Array, Two Pointers, Simulation
• 2107. Find Unique Binary String - MediumTopics: Array, Hash Table, String, Backtracking
• 903. Implement Rand10() Using Rand7() - MediumTopics: Math, Rejection Sampling, Randomized, Probability and Statistics
• 3764. Maximum Sum With at Most K Elements - MediumTopics: Array, Greedy, Sorting, Heap (Priority Queue), Matrix
• 1289. Day of the Week - EasyTopics: Math
• 973. Stamping The Sequence - HardTopics: String, Stack, Greedy, Queue
• 889. Buddy Strings - EasyTopics: Hash Table, String
• 2157. Smallest K-Length Subsequence With Occurrences of a Letter - HardTopics: String, Stack, Greedy, Monotonic Stack
• 1348. Maximum Score Of Spliced Array - HardTopics: Array, Dynamic Programming
• 3706. Smallest Substring With Identical Characters II - HardTopics: String, Binary Search
• 3065. Display the First Three Rows - EasyTopics:
• 2414. Move Pieces to Obtain a String - MediumTopics: Two Pointers, String
• 2387. Partition Array Such That Maximum Difference Is K - MediumTopics: Array, Greedy, Sorting
• 436. Find Right Interval - MediumTopics: Array, Binary Search, Sorting
• 610. Triangle Judgement - EasyTopics: Database
• 2691. Count Vowel Strings in Ranges - MediumTopics: Array, String, Prefix Sum
• 1301. Reformat Department Table - EasyTopics: Database
• 1812. Reformat Phone Number - EasyTopics: String
• 1483. Rank Teams by Votes - MediumTopics: Array, Hash Table, String, Sorting, Counting
• 1413. Maximum Side Length of a Square with Sum Less than or Equal to Threshold - MediumTopics: Array, Binary Search, Matrix, Prefix Sum
• 343. Integer Break - MediumTopics: Math, Dynamic Programming
• 1881. Closest Subsequence Sum - HardTopics: Array, Two Pointers, Dynamic Programming, Bit Manipulation, Sorting, Bitmask
• 1612. Avoid Flood in The City - MediumTopics: Array, Hash Table, Binary Search, Greedy, Heap (Priority Queue)
• 1751. Slowest Key - EasyTopics: Array, String
• 3510. Maximize the Total Height of Unique Towers - MediumTopics: Array, Greedy, Sorting
• 606. Construct String from Binary Tree - MediumTopics: String, Tree, Depth-First Search, Binary Tree
• 3733. Length of Longest V-Shaped Diagonal Segment - HardTopics: Array, Dynamic Programming, Memoization, Matrix
• 2583. Divide Nodes Into the Maximum Number of Groups - HardTopics: Depth-First Search, Breadth-First Search, Union Find, Graph
• 1733. Maximum Number of Visible Points - HardTopics: Array, Math, Geometry, Sliding Window, Sorting
• 689. Maximum Sum of 3 Non-Overlapping Subarrays - HardTopics: Array, Dynamic Programming, Sliding Window, Prefix Sum
• 1217. Relative Sort Array - EasyTopics: Array, Hash Table, Sorting, Counting Sort
• 1409. Minimum Number of Flips to Convert Binary Matrix to Zero Matrix - HardTopics: Array, Hash Table, Bit Manipulation, Breadth-First Search, Matrix
• 2716. Prime Subtraction Operation - MediumTopics: Array, Math, Binary Search, Greedy, Number Theory
• 2524. Largest Positive Integer That Exists With Its Negative - EasyTopics: Array, Hash Table, Two Pointers, Sorting
• 3607. Minimum Division Operations to Make Array Non Decreasing - MediumTopics: Array, Math, Greedy, Number Theory
• 3420. Find Occurrences of an Element in an Array - MediumTopics: Array, Hash Table
• 1229. Shortest Path with Alternating Colors - MediumTopics: Breadth-First Search, Graph
• 1501. Circle and Rectangle Overlapping - MediumTopics: Math, Geometry
• 2492. Length of the Longest Alphabetical Continuous Substring - MediumTopics: String
• 2148. Minimum Number of Moves to Seat Everyone - EasyTopics: Array, Greedy, Sorting, Counting Sort
• 2724. Convert an Array Into a 2D Array With Conditions - MediumTopics: Array, Hash Table
• 1804. Maximum Binary String After Change - MediumTopics: String, Greedy
• 2491. Smallest Even Multiple - EasyTopics: Math, Number Theory
• 804. Rotated Digits - MediumTopics: Math, Dynamic Programming
• 2903. Insert Greatest Common Divisors in Linked List - MediumTopics: Linked List, Math, Number Theory
• 1476. Count Negative Numbers in a Sorted Matrix - EasyTopics: Array, Binary Search, Matrix
• 1769. Get Maximum in Generated Array - EasyTopics: Array, Simulation
• 330. Patching Array - HardTopics: Array, Greedy
• 3397. Find the Integer Added to Array I - EasyTopics: Array
• 729. My Calendar I - MediumTopics: Array, Binary Search, Design, Segment Tree, Ordered Set
• 1954. Replace All Digits with Characters - EasyTopics: String
• 2104. Operations on Tree - MediumTopics: Array, Hash Table, Tree, Depth-First Search, Breadth-First Search, Design
• 3429. Special Array I - EasyTopics: Array
• 2905. Count Paths That Can Form a Palindrome in a Tree - HardTopics: Dynamic Programming, Bit Manipulation, Tree, Depth-First Search, Bitmask
• 855. Count Unique Characters of All Substrings of a Given String - HardTopics: Hash Table, String, Dynamic Programming
• 3783. Permutations IV - HardTopics: Array, Math, Combinatorics, Enumeration
• 376. Wiggle Subsequence - MediumTopics: Array, Dynamic Programming, Greedy
• 1407. Group the People Given the Group Size They Belong To - MediumTopics: Array, Hash Table, Greedy
• 2545. Height of Binary Tree After Subtree Removal Queries - HardTopics: Array, Tree, Depth-First Search, Breadth-First Search, Binary Tree
• 3631. Count K-Reducible Numbers Less Than N - HardTopics: Math, String, Dynamic Programming, Combinatorics
• 3487. Find Maximum Removals From Source String - MediumTopics: Array, Hash Table, Two Pointers, String, Dynamic Programming
• 1581. The k Strongest Values in an Array - MediumTopics: Array, Two Pointers, Sorting
• 1569. Max Dot Product of Two Subsequences - HardTopics: Array, Dynamic Programming
• 825. Max Increase to Keep City Skyline - MediumTopics: Array, Greedy, Matrix
• 2661. Smallest Missing Non-negative Integer After Operations - MediumTopics: Array, Hash Table, Math, Greedy
• 1012. Equal Rational Numbers - HardTopics: Math, String
• 1815. Checking Existence of Edge Length Limited Paths - HardTopics: Array, Two Pointers, Union Find, Graph, Sorting
• 2190. Count Common Words With One Occurrence - EasyTopics: Array, Hash Table, String, Counting
• 2543. Most Popular Video Creator - MediumTopics: Array, Hash Table, String, Sorting, Heap (Priority Queue)
• 3996. Find Books with Polarized Opinions - EasyTopics: