| 71. Simplify Path | | | Solve | Medium | | |
| 114. Flatten Binary Tree to Linked List | | | Solve | Medium | | |
| 143. Reorder List | | | Solve | Medium | | |
| 150. Evaluate Reverse Polish Notation | | | Solve | Medium | | |
| 155. Min Stack | | | Solve | Medium | | |
| 173. Binary Search Tree Iterator | | | Solve | Medium | | |
| 227. Basic Calculator II | | | Solve | Medium | | |
| 255. Verify Preorder Sequence in Binary Search Tree | | | Solve | Medium | | |
| 316. Remove Duplicate Letters | | | Solve | Medium | | |
| 331. Verify Preorder Serialization of a Binary Tree | | | Solve | Medium | | |
| 341. Flatten Nested List Iterator | | | Solve | Medium | | |
| 364. Nested List Weight Sum II | | | Solve | Medium | | |
| 385. Mini Parser | | | Solve | Medium | | |
| 388. Longest Absolute File Path | | | Solve | Medium | | |
| 394. Decode String | | | Solve | Medium | | |
| 402. Remove K Digits | | | Solve | Medium | | |
| 426. Convert Binary Search Tree to Sorted Doubly Linked List | | | Solve | Medium | | |
| 439. Ternary Expression Parser | | | Solve | Medium | | |
| 445. Add Two Numbers II | | | Solve | Medium | | |
| 456. 132 Pattern | | | Solve | Medium | | |
| 484. Find Permutation | | | Solve | Medium | | |
| 503. Next Greater Element II | | | Solve | Medium | | |
| 536. Construct Binary Tree from String | | | Solve | Medium | | |
| 581. Shortest Unsorted Continuous Subarray | | | Solve | Medium | | |
| 636. Exclusive Time of Functions | | | Solve | Medium | | |
| 654. Maximum Binary Tree | | | Solve | Medium | | |
| 678. Valid Parenthesis String | | | Solve | Medium | | |
| 735. Asteroid Collision | | | Solve | Medium | | |
| 739. Daily Temperatures | | | Solve | Medium | | |
| 769. Max Chunks To Make Sorted | | | Solve | Medium | | |
| 853. Car Fleet | | | Solve | Medium | | |
| 856. Score of Parentheses | | | Solve | Medium | | |
| 880. Decoded String at Index | | | Solve | Medium | | |
| 901. Online Stock Span | | | Solve | Medium | | |
| 907. Sum of Subarray Minimums | | | Solve | Medium | | |
| 921. Minimum Add to Make Parentheses Valid | | | Solve | Medium | | |
| 946. Validate Stack Sequences | | | Solve | Medium | | |
| 962. Maximum Width Ramp | | | Solve | Medium | | |
| 1003. Check If Word Is Valid After Substitutions | | | Solve | Medium | | |
| 1006. Clumsy Factorial | | | Solve | Medium | | |
| 1008. Construct Binary Search Tree from Preorder Traversal | | | Solve | Medium | | |
| 1019. Next Greater Node In Linked List | | | Solve | Medium | | |
| 1081. Smallest Subsequence of Distinct Characters | | | Solve | Medium | | |
| 1111. Maximum Nesting Depth of Two Valid Parentheses Strings | | | Solve | Medium | | |
| 1124. Longest Well-Performing Interval | | | Solve | Medium | | |
| 1130. Minimum Cost Tree From Leaf Values | | | Solve | Medium | | |
| 1190. Reverse Substrings Between Each Pair of Parentheses | | | Solve | Medium | | |
| 1209. Remove All Adjacent Duplicates in String II | | | Solve | Medium | | |
| 1214. Two Sum BSTs | | | Solve | Medium | | |
| 1249. Minimum Remove to Make Valid Parentheses | | | Solve | Medium | | |
