hdu 5339 暴力枚举

题意：BC上有中文版的题

思路： 降序排序一次   暴力即可    时间复杂度为O（2 ^n）

#include <iostream>#include "stdio.h"#include "stdlib.h"#include "string.h"#include "math.h"#include "algorithm"#include <queue>using namespace std;#define modulo 1000000007int minn,ss[21],n,a;int cmp(int a,int b){    return a>b;}void dfs(int x,int y,int z){    if(!y) minn=min(z,minn);    if(x<n) {        dfs(x+1,y%ss[x],z+1);        dfs(x+1,y,z);    }    else return;}int main(){    int t;    scanf("%d",&t);    while(t--)    {        minn=21;        scanf("%d%d",&n,&a);        for(int i=0;i<n;i++)            scanf("%d",&ss[i]);        sort(ss,ss+n,cmp);        dfs(0,a,0);        printf("%d\n",minn!=21?minn:-1);    }}