hdu5339

所选的数比当前的数大的话就失去意义了 所以要保证最小每一步所选的取余的数都不能大于当前被取余的数

数据范围很小 直接暴力dfs即可 

#include<cstdio>
#include<cstring>
#include<stack>
#include<vector>
#include<queue>
#include<cmath>
#include<cstdlib>
#include<iostream>
#include<algorithm>
using namespace std;
const int oo = 0x3f3f3f3f;
const int maxn = 1e6+117;
const int mod = 1e9+7;
typedef unsigned long long LL;
typedef double de;
int b[maxn], ans, vis[maxn], n;
int cmp(int a, int b)
{
    return a > b;
}
void dfs(int x, int step, int m)
{
    if(x == n+1)
    {
        if(m == 0)
        ans = min(ans, step);
        return ;
    }
    for(int i = x; i <= n; i++)
    {
        if(vis[i] == 0 && b[i] <= m)
        {
            vis[i] = 1;
            dfs(i+1, step+1, m%b[i]);
            vis[i] = 0;
        }
    }
    dfs(x+1, step, m);
}
int main()
{
    int T, i, a;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d %d", &n, &a);

        ans = oo;memset(vis, 0, sizeof(vis));

        for(i = 1; i <= n; i++)
            scanf("%d", &b[i]);
            
        sort(b+1, b+1+n, cmp);
        dfs(1, 0, a);

        if(ans != oo) printf("%d
", ans);
        else printf("-1
");
    }
    return 0;
}