leetcode: (104) Maximum Depth of Binary Tree

【Question】

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.
利用递归

/**
* 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) {
int hl,hr,max;
if(root!=NULL)
{
hl=maxDepth(root->left);
hr=maxDepth(root->right);
max=hl>hr?hl:hr;
return (max+1);
}
else
return 0;
}
};