python/TangDou/LuoGuBook/P5719.cpp

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, k;
    int Asum = 0, Bsum;
    cin >> n >> k;
    for (int i = k; i <= n; i += k) Asum += i;
    Bsum = (1 + n) * n / 2 - Asum;
    printf("%.1lf ", double(Asum) / (n / k));
    printf("%.1lf ", double(Bsum) / (n - n / k));
    return 0;
}