Why Practice Trees?
Tree problems are the foundation for Graphs and Dynamic Programming on Trees. They are extremely common in mid-level to senior FAANG interviews.
Hand-Picked Problems
| Problem | Difficulty | Key Pattern |
|---|---|---|
| Maximum Depth of Binary Tree | Easy | Recursive DFS |
| Invert Binary Tree | Easy | Recursion |
| Binary Tree Level Order Traversal | Medium | BFS |
| Validate Binary Search Tree | Medium | Range/In-order |
| Lowest Common Ancestor of a Binary Tree | Medium | Post-order |
| Binary Tree Zigzag Level Order Traversal | Medium | BFS + Deque |
| Path Sum II | Medium | Backtracking |
| Diameter of Binary Tree | Easy | Global State |
| Binary Tree Maximum Path Sum | Hard | Advanced Post-order |
| Serialize and Deserialize Binary Tree | Hard | BFS/DFS Design |
Interview Tip
Always clarify: "Is it a Binary Search Tree or just a regular Binary Tree?" This completely changes the optimal approach.