Osu! http://acm.hdu.edu.cn/showproblem.php?pid=5003

 1 #include<cstdio> 2 #include<algorithm> 3 using namespace std; 4 int a[64]; 5 int main(){ 6     int t,n; 7     while(~scanf("%d",&t)){ 8         while(t--){ 9             scanf("%d",&n);10             for(int i=0;i<n;i++){11                 scanf("%d",&a[i]);12             }13             sort(a,a+n);14             double ans=0,mul=1;15             for(int i=n-1;i>=0;i--){16                 ans+=a[i]*mul;17                 mul*=0.95;18             }19             printf("%.10f\n",ans);20         }21     }22     return 0;23 }