[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);    }};