翻译

给定一个二叉树，找出它的最大深度。最大深度是指的从根节点一直到最远的叶节点中所有的节点数目。

原文

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.

代码

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