| 1. Two Sum | Hash Table | Easy |
| 2. Add Two Numbers | Linked List | Medium |
| 3. Longest Substring Without Repeating Characters | Sliding Window | Medium |
| 5. Longest Palindromic Substring | String Manipulation | Dynamic Programming | Medium |
| 6. Zigzag Conversion | String Manipulation | Medium |
| 10. Regular Expression Matching | String Manipulation | Dynamic Programming | Hard |
| 11. Container With Most Water | Two Pointers | Medium |
| 12. Integer to Roman | String Manipulation | Medium |
| 13. Roman to Integer | String Manipulation | Easy |
| 15. 3Sum | Hash Table | Medium |
| 17. Letter Combinations of a Phone Number | String Manipulation | Medium |
| 19. Remove Nth Node From End of List | Linked List | Medium |
| 22. Generate Parentheses | Recursion | String Manipulation | Dynamic Programming | Medium |
| 23. Merge k Sorted Lists | Linked List | Heap | Hard |
| 26. Remove Duplicates from Sorted Array | Two Pointers | Easy |
| 27. Remove Element | Two Pointers | Easy |
| 30. Substring with Concatenation of All Words | Sliding Window | Hash Table | Hard |
| 33. Search in Rotated Sorted Array | Binary Search | Array | Medium |
| 34. Find First and Last Position of Element in Sorted Array | Binary Search | Array | Medium |
| 35. Search Insert Position | Binary Search | Easy |
| 36. Valid Sudoku | 2D Array | Medium |
| 39. Combination Sum | Backtracking | Medium |
| 42. Trapping Rain Water | Two Pointers | Hard |
| 45. Jump Game II | Dynamic Programming | Greedy | Medium |
| 46. Permutations | Backtracking | Medium |
| 48. Rotate Image | 2D Array | Medium |
| 50. Pow(x, n) | Mathematics | Recursion | Medium |
| 52. N-Queens II | Backtracking | Hard |
| 53. Maximum Subarray | Array | Dynamic Programming | Medium |
| 54. Spiral Matrix | 2D Array | Medium |
| 55. Jump Game | Dynamic Programming | Medium |
| 57. Insert Interval | Array | Medium |
| 61. Rotate List | Linked List | Medium |
| 63. Unique Paths II | 2D Array | Dynamic Programming | Medium |
| 64. Minimum Path Sum | Dynamic Programming | Medium |
| 68. Text Justification | String Manipulation | Hard |
| 69. Sqrt(x) | Mathematics | Easy |
| 70. Climbing Stairs | Dynamic Programming | Easy |
| 71. Simplify Path | String Manipulation | Stack | Medium |
| 73. Set Matrix Zeroes | 2D Array | Medium |
| 74. Search a 2D Matrix | 2D Array | Medium |
| 76. Minimum Window Substring | String Manipulation | Sliding Window | Hard |
| 77. Combinations | Backtracking | Medium |
| 79. Word Search | Backtracking | String Manipulation | Medium |
| 80. Remove Duplicates from Sorted Array II | Array | Two Pointers | Medium |
| 82. Remove Duplicates from Sorted List II | Linked List | Medium |
| 86. Partition List | Linked List | Medium |
| 88. Merge Sorted Arrays | Array | Two Pointers | Easy |
| 92. Reverse Linked List II | Linked List | Medium |
| 97. Interleaving String | Dynamic Programming | Medium |
| 98. Validate Binary Search Tree | Binary Search | Tree | Medium |
| 102. Binary Tree Level Order Traversal | Tree | BFS | Medium |
| 103. Binary Tree Zigzag Level Order Traversal | Tree | BFS | Medium |
| 104. Maximum Depth of Binary Tree | Tree | Easy |
| 105. Construct Binary Tree from Preorder and Inorder Traversal | Tree | Medium |
| 106. Construct Binary Tree from Inorder and Postorder Traversal | Tree | Medium |
| 108. Convert Sorted Array to Binary Search Tree | Tree | Medium |
| 112. Path Sum | Tree | Easy |
| 114. Flatten Binary Tree to Linked List | Tree | Medium |
| 117. Populating Next Right Pointers in Each Node II | Tree | Medium |
| 120. Triangle | Dynamic Programming | Medium |
| 125. Valid Palindrome | Two Pointers | Easy |
| 127. Word Ladder | Graph | BFS | Hard |
| 128. Longest Consecutive Sequence | Hash Table | Medium |
| 129. Sum Root to Leaf Numbers | Tree | DFS | Medium |
| 130. Surrounded Regions | 2D Array | DFS | Medium |
| 133. Clone Graph | Graph | Medium |
| 135. Candy | Array | Greedy | Hard |
| 136. Single Number | Bit Manipulation | Easy |
| 138. Copy List with Random Pointer | Linked List | Medium |
| 139. Word Break | Dynamic Programming | Medium |
| 141. Linked List Cycle | Linked List | Easy |
| 146. LRU Cache | Hash Table | Linked List | Medium |
| 148. Sort List | Divide and Conquer | Linked List | Medium |
| 150. Evaluate Reverse Polish Notation | Stack | Medium |
| 153. Find Minimum in Rotated Sorted Array | Linked List | Binary Search | Medium |
| 155. Min Stack | Stack | Medium |
| 167. Two Sum II - Input Array Is Sorted | Two Pointers | Medium |
| 169. Majority Element | Array | Easy |
| 172. Factorial Trailing Zeroes | Mathematics | Medium |
| 173. Binary Search Tree Iterator | Tree | Medium |
| 189. Rotate Array | Array | Medium |
| 198. House Robber | Dynamic Programming | Medium |
| 199. Binary Tree Right Side View | Tree | Medium |
| 200. Number of Islands | 2D Array | Medium |
| 207. Course Schedule | Graph | DFS | Medium |
| 208. Implement Trie (Prefix Tree) | Trie | Medium |
| 209. Minimum Size Subarray Sum | Sliding Window | Medium |
| 210. Course Schedule II | Graph | Medium |
| 211. Design Add and Search Words Data Structure | Trie | Medium |
| 212. Word Search II | Trie | String Manipulation | Backtracking | Medium |
| 215. Kth Largest Element in an Array | Heap | Medium |
| 224. Basic Calculator | Stack | String Manipulation | Hard |
| 226. Invert Binary Tree | Tree | Easy |
| 230. Kth Smallest Element in a BST | Tree | Medium |
| 237. Delete Node in a Linked List | Linked List | Medium |
| 238. Product of Array Except Self | Array | Medium |
| 274. H-Index | Array | Medium |
| 289. Game of Life | 2D Array | Medium |
| 300. Longest Increasing Subsequence | Binary Search | Medium |
| 322. Coin Change | Dynamic Programming | Medium |
| 373. Find K Pairs with Smallest Sums | Heap | Array | Medium |
| 399. Evaluate Division | Graph | BFS | Medium |
| 408. Valid Word Abbreviation | String Manipulation | Two Pointers | Easy |
| 427. Construct Quad Tree | Tree | Medium |
| 433. Minimum Genetic Mutation | Graph | BFS | Medium |
| 452. Minimum Number of Arrows to Burst Balloons | Greedy | Sorting | Medium |
| 480. Sliding Window Median | Sliding Window | Heap | Hard |
| 502. IPO | Heap | Array | Hard |
| 518. Coin Change II | Dynamic Programming | Medium |
| 530. Minimum Absolute Difference in BST | Tree | DFS | Easy |
| 559. Maximum Depth of N-ary Tree | Tree | Easy |
| 622. Design Circular Queue | Array | Linked List | Medium |
| 684. Redundant Connection | Graph | Union Find | Medium |
| 695. Max Area of Island | 2D Array | DFS | Medium |
| 746. Min Cost Climbing Stairs | Dynamic Programming | Easy |
| 802. Find Eventual Safe States | Graph | Recursion | DFS | Medium |
| 819. Most Common Word | Hash Table | Easy |
| 827. Making A Large Island | Graph | DFS | Hard |
| 909. Snakes and Ladders | 2D Array | Graph | BFS | Medium |
| 918. Maximum Sum Circular Subarray | Kadane’s Algorithm | Array | Medium |
| 983. Minimum Cost For Tickets | Dynamic Programming | Medium |
| 1079. Letter Tile Possibilities | Backtracking | Medium |
| 1229. Meeting Scheduler | Two Pointers | Sorting | Medium |
| 1232. Check If It Is a Straight Line | Mathematics | Easy |
| 1267. Count Servers that Communicate | 2D Array | Hash Table | Medium |
| 1352. Product of the Last K Numbers | Prefix Sum | Medium |
| 1415. The k-th Lexicographical String of All Happy Strings of Length n | Backtracking | Medium |
| 1452. People Whose List of Favorite Companies Is Not a Subset of Another List | Hash Table | Medium |
| 1462. Course Schedule IV | Graph | Medium |
| 1657. Determine if Two Strings Are Close | Hash Table | Medium |
| 1718. Construct the Lexicographically Largest Valid Sequence | Backtracking | Medium |
| 1726. Tuple with Same Product | Hash Table | Medium |
| 1730. Shortest Path to Get Food | BFS | 2D Array | Medium |
| 1765. Map of Highest Peak | BFS | 2D Array | Medium |
| 1910. Remove All Occurrences of a Substring | String Manipulation | Medium |
| 1980. Find Unique Binary String | String Manipulation | Medium |
| 2017. Grid Game | 2D Array | Medium |
| 2127. Maximum Employees to Be Invited to a Meeting | Graph | DFS | Hard |
| 2342. Max Sum of a Pair With Equal Sum of Digits | Hash Table | Medium |
| 2349. Design a Number Container System | Heap | Hash Table | Medium |
| 2364. Count Number of Bad Pairs | Mathematics | Hash Table | Medium |
| 2375. Construct Smallest Number From DI String | Backtracking | Medium |
| 2425. Bitwise XOR of All Pairings | Bit Manipulation | Medium |
| 2658. Maximum Number of Fish in a Grid | 2D Array | DFS | Medium |
| 2661. First Completely Painted Row or Column | 2D Array | Hash Table | Medium |
| 2683. Neighboring Bitwise XOR | Bit Manipulation | Medium |
| 2698. Find the Punishment Number of an Integer | Recursion | String Manipulation | Medium |
| 2948. Make Lexicographically Smallest Array by Swapping Elements | Array | Queue | Medium |
| 3066. Minimum Operations to Exceed Threshold Value II | Heap | Medium |
| 3160. Find the Number of Distinct Colors Among the Balls | Hash Table | Medium |