(水)hdu 5003

Osu!

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 737    Accepted Submission(s): 371
Special Judge

Problem Description

Osu! is a famous music game that attracts a lot of people. In osu!, there is a performance scoring system, which evaluates your performance. Each song you have played will have a score. And the system will sort all you scores in descending order. After that, the i-th song scored a_i will add 0.95^(i-1)*a_i to your total score.

Now you are given the task to write a calculator for this system.

 

 

Input

The first line contains an integer T, denoting the number of the test cases.

For each test case, the first line contains an integer n, denoting the number of songs you have played. The second line contains n integers a₁, a₂, ..., a_n separated by a single space, denoting the score of each song.

T<=20, n<=50, 1<=a_i<=500.

 

 

Output

For each test case, output one line for the answer.

Your answers will be considered correct if its absolute error is smaller than 1e-5.

 

 

Sample Input

1 2 530 478

 

 

Sample Output

984.1000000000

 

 

Source

2014 ACM/ICPC Asia Regional Anshan Online

 

 

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<cstdlib>
#include<algorithm>
using namespace std;
int tt,n,a[52];
bool cmp(int x,int y)
{
      return x>y;
}
int main()
{
      scanf("%d",&tt);
      while(tt--)
      {
            scanf("%d",&n);
            for(int i=1;i<=n;i++)
                  scanf("%d",&a[i]);
            sort(a+1,a+1+n,cmp);
            double ans=0;
            for(int i=1;i<=n;i++)
                  ans+=pow(0.95,i-1)*a[i];
            printf("%.10lf\n",ans);
      }
      return 0;
}