Problem

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.

Example

Given a binary tree as follow:

  1
 / \ 
2   3
   / \
  4   5

The maximum depth is 3.

Note

求二叉树最大深度。基础题，递归，注意最后的+ 1.

Solution

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;
    }
}