leetcode:Minimum Depth of Binary Tree

/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/

/*
使用层序遍历的方法计算二叉树最短路径长度，当遇到某个结点没有孩子结点时，找到最短路径。
*/
class Solution{
public:
	int  minDepth(TreeNode *root)
	{
		if(root==NULL)
			return 0;
		int depth=0;
		vector<TreeNode*>vec;
		vec.push_back(root);
		TreeNode *p;
		int cur=0;
		int last=1;
		while(cur<vec.size())
		{
			p=vec[cur];
			if(cur==last)
			{
				++depth;
				last=vec.size();
			}
			++cur;
			if(!p->left&&!p->right)
			{
				break;
			}
			if(p->left)
				vec.push_back(p->left);
			if(p->right)
				vec.push_back(p->right);
			
		}
		++depth;
		return depth;
	}
};