Codeforces700A As Fast As Possible 数学推理

 

设车载距离xl

每拨等t＝（2xl）／（v1+v2）

最后一波要正好到头

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;

int main()
{
    int n,k;
    double l,v1,v2;
    while(~scanf("%d%lf%lf%lf%d",&n,&l,&v1,&v2,&k))
    {
        int g = n / k + (n % k != 0);
        double  a = (v1 + v2)*l/(v1+v2+2*(g-1)*v1);
        double sum = a / v2 + (l-a)/v1;
        printf("%.10f\n",sum);
    }
    return 0;
}