| 5. Longest Palindromic Substring | Solution | Solve | Medium | | |
| 12. Integer to Roman | Solution | Solve | Medium | | |
| 17. Letter Combinations of a Phone Number | Solution | Solve | Medium | | |
| 31. Next Permutation | Solution | Solve | Medium | | |
| 34. Find First and Last Position of Element in Sorted Array | Solution | Solve | Medium | | |
| 39. Combination Sum | Solution | Solve | Medium | | |
| 46. Permutations | Solution | Solve | Medium | | |
| 49. Group Anagrams | Solution | Solve | Medium | | |
| 50. Pow(x, n) | Solution | Solve | Medium | | |
| 53. Maximum Subarray | Solution | Solve | Medium | | |
| 56. Merge Intervals | Solution | Solve | Medium | | |
| 71. Simplify Path | Solution | Solve | Medium | | |
| 79. Word Search | Solution | Solve | Medium | | |
| 98. Validate Binary Search Tree | Solution | Solve | Medium | | |
| 103. Binary Tree Zigzag Level Order Traversal | Solution | Solve | Medium | | |
| 146. LRU Cache | Solution | Solve | Medium | | |
| 150. Evaluate Reverse Polish Notation | Solution | Solve | Medium | | |
| 151. Reverse Words in a String | Solution | Solve | Medium | | |
| 155. Min Stack | Solution | Solve | Medium | | |
| 200. Number of Islands | Solution | Solve | Medium | | |
| 204. Count Primes | Solution | Solve | Medium | | |
| 207. Course Schedule | Solution | Solve | Medium | | |
| 208. Implement Trie (Prefix Tree) | Solution | Solve | Medium | | |
| 210. Course Schedule II | Solution | Solve | Medium | | |
| 221. Maximal Square | Solution | Solve | Medium | | |
| 253. Meeting Rooms II | Solution | Solve | Medium | | |
| 256. Paint House | Solution | Solve | Medium | | |
| 279. Perfect Squares | Solution | Solve | Medium | | |
| 287. Find the Duplicate Number | Solution | Solve | Medium | | |
| 300. Longest Increasing Subsequence | Solution | Solve | Medium | | |
| 343. Integer Break | Solution | Solve | Medium | | |
| 348. Design Tic-Tac-Toe | Solution | Solve | Medium | | |
| 380. Insert Delete GetRandom O(1) | Solution | Solve | Medium | | |
| 399. Evaluate Division | Solution | Solve | Medium | | |
| 622. Design Circular Queue | Solution | Solve | Medium | | |
| 647. Palindromic Substrings | Solution | Solve | Medium | | |
| 718. Maximum Length of Repeated Subarray | Solution | Solve | Medium | | |
| 740. Delete and Earn | Solution | Solve | Medium | | |
| 767. Reorganize String | Solution | Solve | Medium | | |
| 875. Koko Eating Bananas | Solution | Solve | Medium | | |
| 981. Time Based Key-Value Store | Solution | Solve | Medium | | |
| 1004. Max Consecutive Ones III | Solution | Solve | Medium | | |
| 1010. Pairs of Songs With Total Durations Divisible by 60 | Solution | Solve | Medium | | |
| 1048. Longest String Chain | Solution | Solve | Medium | | |
| 1155. Number of Dice Rolls With Target Sum | Solution | Solve | Medium | | |
| 1197. Minimum Knight Moves | Solution | Solve | Medium | | |
| 1229. Meeting Scheduler | Solution | Solve | Medium | | |
| 1244. Design A Leaderboard | Solution | Solve | Medium | | |
| 1268. Search Suggestions System | Solution | Solve | Medium | | |
| 1670. Design Front Middle Back Queue | Solution | Solve | Medium | | |
