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.

给定一个二叉树，返回其最深支路。

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    int maxDepth(TreeNode *root) {        if(root==NULL) return 0;        if(root->left==NULL && root->right==NULL) return 1;        int leftdepth=maxDepth(root->left);        int rightdepth=maxDepth(root->right);        return max(leftdepth,rightdepth)+1;    }};