#104
Maximum Depth of Binary Tree
easy · verified · 78% accepted · 14,233 likes · top 89%
tree · depth-first search · breadth-first search · binary tree
Description
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.
Example 1:
Input: root = [3,9,20,null,null,15,7]
Output: 3
Example 2:
Input: root = [1,null,2]
Output: 2
Solution