Leetcode Series. No 104: Maximum Depth of Binary Tree

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

As always, follow the comments for each line.

In this solution, the time complexity is O(n) where “n” is the number of nodes in the tree.

From my comments on the code, if you have any questions or comments, feel free to reach out.