[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.

DFS

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int maxD(TreeNode *root,int depth){
if(root->left==NULL && root->right == NULL) return depth;
else if(root->left!=NULL && root->right == NULL) return maxD(root->left,depth+1);
else if(root->left==NULL && root->right != NULL) return maxD(root->right,depth+1);
else return max(maxD(root->left,depth+1),maxD(root->right,depth+1));
}
int maxDepth(TreeNode *root) {
if(root == NULL) return 0;
return maxD(root,1);
}
};