| 100. Same Tree | Solution | Solve | Easy | | |
| 101. Symmetric Tree | Solution | Solve | Easy | | |
| 102. Binary Tree Level Order Traversal | Solution | Solve | Medium | | |
| 103. Binary Tree Zigzag Level Order Traversal | Solution | Solve | Medium | | |
| 104. Maximum Depth of Binary Tree | Solution | Solve | Easy | | |
| 107. Binary Tree Level Order Traversal II | Solution | Solve | Medium | | |
| 111. Minimum Depth of Binary Tree | Solution | Solve | Easy | | |
| 112. Path Sum | Solution | Solve | Easy | | |
| 116. Populating Next Right Pointers in Each Node | Solution | Solve | Medium | | |
| 117. Populating Next Right Pointers in Each Node II | Solution | Solve | Medium | | |
| 126. Word Ladder II | Solution | Solve | Hard | | |
| 127. Word Ladder | Solution | Solve | Hard | | |
| 130. Surrounded Regions | Solution | Solve | Medium | | |
| 133. Clone Graph | Solution | Solve | Medium | | |
| 199. Binary Tree Right Side View | Solution | Solve | Medium | | |
| 200. Number of Islands | Solution | Solve | Medium | | |
| 207. Course Schedule | Solution | Solve | Medium | | |
| 210. Course Schedule II | Solution | Solve | Medium | | |
| 226. Invert Binary Tree | Solution | Solve | Easy | | |
| 261. Graph Valid Tree | Solution | Solve | Medium | | |
| 269. Alien Dictionary | Solution | Solve | Hard | | |
| 279. Perfect Squares | Solution | Solve | Medium | | |
| 286. Walls and Gates | Solution | Solve | Medium | | |
| 297. Serialize and Deserialize Binary Tree | Solution | Solve | Hard | | |
| 301. Remove Invalid Parentheses | Solution | Solve | Hard | | |
| 302. Smallest Rectangle Enclosing Black Pixels | Solution | Solve | Hard | | |
| 310. Minimum Height Trees | Solution | Solve | Medium | | |
| 314. Binary Tree Vertical Order Traversal | Solution | Solve | Medium | | |
| 317. Shortest Distance from All Buildings | Solution | Solve | Hard | | |
| 322. Coin Change | Solution | Solve | Medium | | |
| 323. Number of Connected Components in an Undirected Graph | Solution | Solve | Medium | | |
| 329. Longest Increasing Path in a Matrix | Solution | Solve | Hard | | |
| 339. Nested List Weight Sum | Solution | Solve | Medium | | |
| 364. Nested List Weight Sum II | Solution | Solve | Medium | | |
| 365. Water and Jug Problem | Solution | Solve | Medium | | |
| 399. Evaluate Division | Solution | Solve | Medium | | |
| 404. Sum of Left Leaves | Solution | Solve | Easy | | |
| 407. Trapping Rain Water II | Solution | Solve | Hard | | |
| 417. Pacific Atlantic Water Flow | Solution | Solve | Medium | | |
| 428. Serialize and Deserialize N-ary Tree | Solution | Solve | Hard | | |
| 429. N-ary Tree Level Order Traversal | Solution | Solve | Medium | | |
| 431. Encode N-ary Tree to Binary Tree | Solution | Solve | Hard | - | |
| 433. Minimum Genetic Mutation | Solution | Solve | Medium | | |
| 449. Serialize and Deserialize BST | Solution | Solve | Medium | | |
| 463. Island Perimeter | Solution | Solve | Easy | | |
| 488. Zuma Game | Solution | Solve | Hard | | |
| 490. The Maze | Solution | Solve | Medium | | |
| 499. The Maze III | Solution | Solve | Hard | | |
| 505. The Maze II | Solution | Solve | Medium | | |
| 513. Find Bottom Left Tree Value | Solution | Solve | Medium | | |
