leetcode Maximum Depth of Binary Tree

Maximum Depth of Binary Tree

题目详情：

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.

解题方法：

递归算法：若root为空，则返回0。否则返回其左子树maximum depth +1 和 右子树maximum depth + 1的较大者。

代码详情：

/**
 * 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;
       } else {
           int num1 = maxDepth(root->left);
           int num2 = maxDepth(root->right);
           return num1>=num2 ? num1+1:num2+1;
       }
    }
    
};