Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

 

递归啦。

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 minDepth(TreeNode* root) {13         if(!root) return 0;14         if(root->left==NULL && root->right==NULL) return 1;15         int left = (root->left)?minDepth(root->left):INT_MAX;16         int right = (root->right)?minDepth(root->right):INT_MAX;17         return min(left,right)+1;18     }19 };