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.

一目了然，递归。

/**

 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
 
#include <algorithm>
using namespace std;


class Solution {
public:
    int maxDepth(TreeNode *root) {
        if (root == NULL) {
            return 0;
        }
        
        return (max(maxDepth(root->left), maxDepth(root->right)) + 1);
    }
};

======================第二次=======================

/** * 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 maxDepth(TreeNode *root) {        if (root == NULL) {            return 0;        }        else {            return max(maxDepth(root->left), maxDepth(root->right)) + 1;        }    }};