水。。

#include <iostream>
#include <cstdio>
#include <string.h>
#include <queue>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;
#define N 100
double a[N];
bool cmp(double x, double y){
    return x>y;
}
int n;
double quick(double x, int y){
    double ans = 1.0;
    while(y){
        if(y&1)
            ans *= x;
        y >>= 1;
        x *= x;
    }
    return ans;
}
void solve(){
    scanf("%d",&n);
    for(int i = 1; i <= n; i++)scanf("%lf",&a[i]);
    sort(a+1, a+n+1, cmp);
    double ans = 0;
    for(int i = 1; i <= n; i++)
    {
        ans += quick(0.95, i-1) * a[i];
    }
    printf("%.10f\n",ans);
}
int main(){
    int T;scanf("%d",&T);
    while(T--){
        solve();
    }
    return 0;
}

HDU 5003 Osu! 水题 2014 ACM/ICPC Asia Regional Anshan Online