leetcode：Maximum Depth of Binary Tree 【Java】

一、问题描述

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.
二、问题分析

利用递归思想。

三、算法代码

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
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;
    }
}