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.

这一题很简单，就什么都不多说了。数的高度等于子树的高度（子树的高度=左子树的高度或者右子树的高度）+1；

/** * 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;        return Math.max(maxDepth(root.left),maxDepth(root.right))+1;    }}