Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Have you met this question in a real interview? Yes Problem Correction Example Given a binary tree as follow:

  1
 / \ 
2   3
   / \
  4   5

The maximum depth is 3.

递归分治

public class Solution {
    public int maxDepth(TreeNode root) {
        if(root == null) {
            return 0;
        }

        int left = maxDepth(root.left);
        int right = maxDepth(root.right);
        return Math.max(left, right) + 1;
    }
}