第十六周：104. 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.

这道题一行代码就可以解决了，主要就是用到递归的思想。

AC:

/** * 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 maxDepth(TreeNode* root) {        return root == NULL ? 0 : max(maxDepth(root -> left), maxDepth(root -> right)) + 1;    }};