| 1. Two Sum | Solution | Solve | Easy | | |
| 2. Add Two Numbers | Solution | Solve | Medium | | |
| 5. Longest Palindromic Substring | Solution | Solve | Medium | | |
| 12. Integer to Roman | Solution | Solve | Medium | | |
| 13. Roman to Integer | Solution | Solve | Easy | | |
| 18. 4Sum | Solution | Solve | Medium | | |
| 23. Merge k Sorted Lists | Solution | Solve | Hard | | |
| 31. Next Permutation | Solution | Solve | Medium | | |
| 37. Sudoku Solver | Solution | Solve | Hard | | |
| 45. Jump Game II | Solution | Solve | Medium | | |
| 49. Group Anagrams | Solution | Solve | Medium | | |
| 55. Jump Game | Solution | Solve | Medium | | |
| 56. Merge Intervals | Solution | Solve | Medium | | |
| 84. Largest Rectangle in Histogram | Solution | Solve | Hard | | |
| 124. Binary Tree Maximum Path Sum | Solution | Solve | Hard | | |
| 146. LRU Cache | Solution | Solve | Medium | | |
| 164. Maximum Gap | Solution | Solve | Medium | | |
| 200. Number of Islands | Solution | Solve | Medium | | |
| 207. Course Schedule | Solution | Solve | Medium | | |
| 208. Implement Trie (Prefix Tree) | Solution | Solve | Medium | | |
| 209. Minimum Size Subarray Sum | Solution | Solve | Medium | | |
| 210. Course Schedule II | Solution | Solve | Medium | | |
| 211. Design Add and Search Words Data Structure | Solution | Solve | Medium | | |
| 212. Word Search II | Solution | Solve | Hard | | |
| 224. Basic Calculator | Solution | Solve | Hard | | |
| 227. Basic Calculator II | Solution | Solve | Medium | | |
| 239. Sliding Window Maximum | Solution | Solve | Hard | | |
| 286. Walls and Gates | Solution | Solve | Medium | | |
| 296. Best Meeting Point | Solution | Solve | Hard | | |
| 297. Serialize and Deserialize Binary Tree | Solution | Solve | Hard | | |
| 304. Range Sum Query 2D - Immutable | Solution | Solve | Medium | | |
| 314. Binary Tree Vertical Order Traversal | Solution | Solve | Medium | | |
| 317. Shortest Distance from All Buildings | Solution | Solve | Hard | | |
| 329. Longest Increasing Path in a Matrix | Solution | Solve | Hard | | |
| 347. Top K Frequent Elements | Solution | Solve | Medium | | |
| 380. Insert Delete GetRandom O(1) | Solution | Solve | Medium | | |
| 456. 132 Pattern | Solution | Solve | Medium | | |
| 460. LFU Cache | Solution | Solve | Hard | | |
| 480. Sliding Window Median | Solution | Solve | Hard | | |
| 542. 01 Matrix | Solution | Solve | Medium | | |
| 556. Next Greater Element III | Solution | Solve | Medium | | |
| 588. Design In-Memory File System | Solution | Solve | Hard | | |
| 621. Task Scheduler | Solution | Solve | Medium | | |
| 642. Design Search Autocomplete System | Solution | Solve | Hard | | |
| 658. Find K Closest Elements | Solution | Solve | Medium | | |
| 695. Max Area of Island | Solution | Solve | Medium | | |
| 735. Asteroid Collision | Solution | Solve | Medium | | |
| 759. Employee Free Time | Solution | Solve | Hard | | |
| 772. Basic Calculator III | Solution | Solve | Hard | | |
| 778. Swim in Rising Water | Solution | Solve | Hard | | |
