LeetCode104 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. （Easy）

分析：

这个题只需要搞清楚maximum depth的定义，然后用递归求解即可。

代码：

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     int maxDepth(TreeNode* root) {
13         if (root == nullptr) {
14             return 0;
15         }
16         return max( maxDepth(root -> left), maxDepth(root -> right) ) + 1;
17     }
18 };