COGS1487 麻球繁衍

不会做%%http://blog.csdn.net/doom_bringer/article/details/50428503

 #include<bits/stdc++.h>
 #define LL long long
 #define LD long double
 #define  N 100005
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 double f[],p[];
 double ksm(double a, int p)
 {
     double ans=;
     for (;p;p>>=,a*=a)
         if (p&)
             ans*=a;
     return ans;
 }
 int main()
 {
     freopen("tribbles.in","r",stdin);
     freopen("tribbles.out","w",stdout);
     int T=ra();
     for (int t=; t<=T; t++)
     {
         int n=ra(),k=ra(),m=ra();
         for (int i=; i<n; i++) scanf("%lf",&p[i]);
         memset(f,,sizeof(f));
         f[]=; f[]=p[];
         for (int i=; i<=m; i++)
             for (int j=; j<n; j++)
                 f[i]+=p[j]*ksm(f[i-],j);
         printf("Case #%d: %.7lf\n",t,ksm(f[m],k));
     }
     return ;
 }