Syrian Collegiate Programming Contest

F. Door Lock

#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
long double sec(long double a, long double b, long double c)
{
	long  double del = b*b - 4 * a *c;
	long double x1 = (-sqrt(del) - b) / 2*a;
	long double x2 = (sqrt(del) - b) / 2*a;
	if (x1 > 0 && x1 < 0)
		return x1;
	if (x2>0 && x1 < 0)
		return x2;
	return x2;
}
int main()
{
	int c = 1;
	long long m, u, d,t;
	int n;
	cin >> t;
	while (t--)
	{
		cin >> n>> m;	
		m--;
		long  long j =floor (sec(1, 1, -2 * m));
		d = m - (j*(j + 1)) / 2;
		cout << "Case " << c++ << ": ";
		cout << j << " " << d  << endl;
	}
	//cin >> t;
	
}

http://codeforces.com/gym/100500