使网格图至少有一条有效路径的最小代价（队列/双端队列）

题目：https://leetcode-cn.com/problems/minimum-cost-to-make-at-least-one-valid-path-in-a-grid/ 更简洁的做法是用双端队列，当时没相到

class Solution {
public:
    /*
    *队列：把同层次的优先遍历
    */
    struct node{
        int val;
        int x,y;
        node(){}
        node(int _val,int _x,int _y):val(_val),x(_x),y(_y){}
    };
    int m,n;
    bool check(int x,int y ){
        return (x>=0&&x=0&&y