/**
* 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) {
if(root==NULL)
return 0;
int depth_left=maxDepth(root->left);
int depth_right=maxDepth(root->right);
return depth_left>depth_right?depth_left+1:depth_right+1;
}
};
