bzoj1076

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #include<ctime>
 5 #include<cstdlib>
 6 #include<iostream>
 7 #include<algorithm>
 8 #define clr(a,x) memset(a,x,sizeof(a))
 9 #define rep(i,l,r) for(int i=l;i<r;i++)
10 #define b(a) (1<<(a))
11 using namespace std;
12 int read()
13 {
14     char c=getchar();
15     int ans=0,f=1;
16     while(!isdigit(c)){
17         if(c==‘-‘) f=-1;
18         c=getchar();
19     }
20     while(isdigit(c)){
21         ans=ans*10+c-‘0‘;
22         c=getchar();
23     }
24     return ans*f;
25 }
26 const int maxn=16,maxk=102;
27 double dp[maxk][b(maxn)];
28 int v[maxn],q[maxn];
29 int main()
30 {
31     clr(dp,0);
32     int k=read(),n=read();
33     rep(i,0,n){
34         v[i]=read();
35         q[i]=0;
36         int t=read();
37         while(t){
38             q[i]|=b(t-1);
39             t=read();
40         }
41     }
42     for(int i=k-1;i>=0;i--){
43         rep(j,0,b(n)){
44             rep(l,0,n){
45                 if((j&q[l])==q[l])
46                     dp[i][j]+=max(dp[i+1][j|b(l)]+v[l],dp[i+1][j]);
47                 else dp[i][j]+=dp[i+1][j];
48             }
49             dp[i][j]/=n;
50         }
51     }
52     printf("%.6lf",dp[0][0]);
53     return 0;
54 }