Codeforces Round #364 (Div. 2) D. As Fast As Possible（数学推导）

#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;
#define pr(x) cout << #x << ": " << x << "  "
#define pl(x) cout << #x << ": " << x << endl;

struct jibancanyang
{
int n, k;
double l, v1, v2;

void run() {
while (cin >> n >> l >> v1 >> v2 >> k) {
double a = (v2 - v1) /(v2 + v1) * v1 + v1;
double b = (k + n - 1) / k - 1;
double t2 = l / (a * b + v2);
double t1 = (l - v2 * t2) / v1;
printf("%.14f\n", t1 + t2);
}
}

}ac;

int main()
{
#ifdef LOCAL
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif
ac.run();
return 0;
}