AC 40 RE 60，40pts 求调

#include <bits/stdc++.h>
using namespace std;
const int N=20,S=1<<17|1;
int k,n,p[N],s[N];
double dp[N][S];
int main(){
    scanf("%d%d",&k,&n);
    for(int i=1,x;i<=n;++i){
        scanf("%d",p+i);
        while(scanf("%d",&x),x) s[i]|=(1<<x-1);
    }
    for(int i=k;i>=1;--i){
        for(int j=0;j<(1<<n);++j){
            for(int k=1;k<=n;++k){
                if((j&s[k])==s[k]){
                    dp[i][j]+=max(dp[i+1][j],dp[i+1][j|1<<k-1]+p[k]);
                }
                else dp[i][j]+=dp[i+1][j];
            }
            dp[i][j]/=n;
        }
    }
    printf("%.6lf",dp[1][0]);
    return 0;
}
/*
1 2
1 0
2 0
1.500000

6 6
12 2 3 4 5 0
15 5 0
-2 2 4 5 0
-11 2 5 0
5 0
1 2 4 5 0
10.023470
*/