LeetCode --- Minimum Depth of Binary Tree

题目链接

求二叉树最小深度，最小深度指的是：从根节点走到最近的叶子结点的最短长度

附上代码：

 1 /**  2  * Definition for binary tree  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 minDepth(TreeNode *root) { 13         if (root == NULL) return 0; 14         if (root->left == NULL && root->right == NULL) return 1; 15         int ans(0x3f3f3f3f); 16         if (root->left != NULL)  ans = minDepth(root->left); 17         if (root->right != NULL) ans = min(ans, minDepth(root->right)); 18         return ans + 1; 19  } 20 };