104. 二叉树的最大深度

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     int maxDepth(TreeNode* root) {
13         int maxx = 0;
14         if(root != NULL) {
15             maxx++;
16             int left_max = maxDepth(root->left);
17             int right_max = maxDepth(root->right);
18             maxx += max(left_max,right_max);
19         }
20         return maxx;
21     }
22 };