luogu P3802 小魔女帕琪

二次联通门 : luogu P3802 小魔女帕琪

 

 

 

 

/*
    luogu P3802 小魔女帕琪

    套个公式就好
     
*/
#include <cstdio>

#define Max 8

double number[Max];


int main (int argc, char *argv[])
{    
    int M = 7;
    double N(0);
    
    for (int i = 1; i <= M; i ++)
        scanf ("%lf", &number[i]);
        
    for (int i = 1; i <= M; i ++)
        N += number[i];
    
    printf ("%.3lf", 5040 * number[1] / N * number[2] / (N - 1) * number[3] / (N - 2) * number[4] / (N - 3) * number[5] / (N - 4) * number[6] / (N - 5) * number[7]);
    
    return 0;
}