| 297 | Serialize and Deserialize Binary Tree | Hard |
| 310 | Minimum Height Trees | Medium |
| 329 | Longest Increasing Path in a Matrix | Hard |
| 332 | Reconstruct Itinerary | Hard |
| 337 | House Robber III | Medium |
| 341 | Flatten Nested List Iterator | Medium |
| 365 | Water and Jug Problem | Medium |
| 385 | Mini Parser | Medium |
| 386 | Lexicographical Numbers | Medium |
| 388 | Longest Absolute File Path | Medium |
| 399 | Evaluate Division | Medium |
| 404 | Sum of Left Leaves | Easy |
| 417 | Pacific Atlantic Water Flow | Medium |
| 419 | Battleships in a Board | Medium |
| 430 | Flatten a Multilevel Doubly Linked List | Medium |
| 437 | Path Sum III | Medium |
| 449 | Serialize and Deserialize BST | Medium |
| 463 | Island Perimeter | Easy |
| 472 | Concatenated Words | Hard |
| 501 | Find Mode in Binary Search Tree | Easy |
| 508 | Most Frequent Subtree Sum | Medium |
| 513 | Find Bottom Left Tree Value | Medium |
| 514 | Freedom Trail | Hard |
| 515 | Find Largest Value in Each Tree Row | Medium |
| 529 | Minesweeper | Medium |
| 530 | Minimum Absolute Difference in BST | Easy |
| 538 | Convert BST to Greater Tree | Medium |
| 543 | Diameter of Binary Tree | Easy |
| 547 | Friend Circles | Medium |
| 559 | Maximum Depth of N-ary Tree | Easy |