LeetCode: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.

/**
* 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;
if(!root->left&&!root->right)
return 1;
int leftDepth=maxDepth(root->left);
int rightDepth=maxDepth(root->right);

if(leftDepth==0)
return rightDepth+1;
if(rightDepth==0)
return leftDepth+1;
else
return max(rightDepth,leftDepth)+1;
}
};