104. Maximum Depth of Binary Tree

题目：

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.

思路：

看到二叉树的问题，就想到用递归，父节点的深度为两个子节点深度中较大的值再加1.

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;        }else{            int left = maxDepth(root.left);            int right = maxDepth(root.right);            if(left > right){                return left+1;            }else{                return right+1;            }        }    }}