zoj 3827(2014牡丹江现场赛 I题 )

套公式

Sample Input

3
3 bit
25 25 50 //百分数
7 nat
1 2 4 8 16 32 37
10 dit
10 10 10 10 10 10 10 10 10 10
Sample Output

1.500000000000
1.480810832465
1.000000000000

 # include <iostream>
 # include <cstdio>
 # include <cstring>
 # include <algorithm>
 # include <cmath>
 # include <queue>
 # define LL long long
 using namespace std ;

 char s[] ;
 const double esp = 1e-;

 int main ()
 {
     //freopen("in.txt","r",stdin) ;
     int T ;
     scanf("%d" , &T) ;
     while(T--)
     {
         int n ;
         double  p , b ;
         scanf("%d %s" , &n , s) ;
         if (s[] == 'b')
             b =  ;
         else if (s[] == 'n')
             b = exp(1.0) ;
         else
             b =  ;
         int i ;
         double ans =  ;
         for (i =  ; i < n ; i++)
         {
             scanf("%lf" , &p) ;
             if (fabs(p) > esp)
             {
                 p /= 100.0;
                 ans += p * log(p) / log(b);
             }

         }
         printf("%.12lf\n" , -ans) ;

     }

     return  ;
 }