404B - Marathon - CodeForces Solution

#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <fstream>

using namespace std;

long double a, d, n, x, y, s, l, j;

int main()
{
    cout << fixed << setprecision(7);

    cin >> a >> d >> n;

    l = a * 4;

    for (int i = 0; i < n; i++)
    {
        s = fmod((i + 1) * d, l);

        j = 0;

        while (s - a > 0)
        {
            s -= a, j++;
        }

        if (j == 0) x = s, y = 0;
        else if (j == 1) x = a, y = s;
        else if (j == 2) x = a - s, y = a;
        else x = 0, y = a - s;

        cout << x << " " << y << "\n";
    }

    return 0;
}