DSA · Trees · #112
Maximum Depth of Binary Tree
Module 44 · difficulty 2/5·⏱ 30:00starts on first keystroke
Given the `root` of a binary tree, return its **maximum depth**. A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Each node is an object `{ val, left, right }`, where `left` and `right` are either child nodes or `null`. An empty tree is represented by `root === null`. Implement `maxDepth(root)`.
Examples
root = [3,9,20,null,null,15,7]→3— The longest root-to-leaf path is 3 -> 20 -> 15 (or 3 -> 20 -> 7), 3 nodes deep.root = [1,null,2]→2— Path 1 -> 2 is 2 nodes deep.root = []→0— An empty tree has depth 0.
Constraints
- · The number of nodes is in the range [0, 10^4].
- · -100 <= Node.val <= 100
Session phases
A · Clarify
B · Approach
C · Complexity
D · Edges
E · Code
F · Tradeoff
G · Score
Phase A — Clarify
Ask questions about input bounds, types, and edge constraints.
Ask the coach clarifying questions about the problem.
When you've covered this phase, advance to the next.