| Order | Question | Difficulty | Votes |
|---|---|---|---|
| 1 | Binary Tree Inorder Traversal | Easy | |
| 2 | Binary Tree Preorder Traversal | Easy | |
| 3 | Binary Tree Postorder Traversal | Easy | |
| 4 | Convert Sorted Array to Binary Tree | Easy | |
| 5 | Binary Tree Level Order Traversal | Medium | |
| 6 | Binary Tree Zigzag Level Order Traversal | Medium | |
| 7 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | |
| 8 | Serialize and Deserialize Binary Tree | Hard |
| Order | Question | Difficulty | Votes |
|---|---|---|---|
| 1 | Maximum Depth of Binary Tree | Easy | |
| 2 | Same Tree | Easy | |
| 3 | Subtree of Another Tree | Easy | |
| 4 | Invert Binary Tree | Easy | |
| 5 | Path Sum | Easy | |
| 6 | Validate Binary Search Tree | Medium | |
| 7 | Symmmetric Tree | Medium | |
| 8 | K-th Smallest Element in a BST | Medium | |
| 9 | Flatten Binary Tree to Linked List | Medium | |
| 10 | Binary Tree Maximum Path Sum | Hard |