#include <iostream>
#include <stdlib.h>
using namespace std;

#define C 300000;

double genExp(double lambda)
{
	double u, x;
	u = (double)rand() / (RAND_MAX + 1);
	x = -1 / lambda*log(1 - u);
	return x;
}


double genGauss(double medie, double sigma)
{
	double s = 0; int i;
	for (i = 1; i <= 12; i++)
		s += (double)rand() / RAND_MAX;
	return medie + sigma*(s - 6);
}

int main()
{
	//initializari
	int NS = 1000000;
	double pc = 0;
	double STa = 0;
	double lambda = (2 * 1.609) / C;
	//simulare cerere de acces
	for (int i = 0; i < NS; i++)
	{
		//generare cerere
		double m = 20;
		double sigma = (m - 1) / 3.5;
		double c = genExp(lambda);
		double b = genGauss(m, sigma);

		//tratare cerere(calcul timp acces)
		double n = abs(pc - c);

		if (n == 1)
			STa += 2;
		else
			STa += 1.2 + 0.0012 * (n - 1);
		double T = 7200.0 / 60000;
		STa += T / 2;
		STa += b*T / 255; //ns = 255
		pc = c;
	}
	//calcul timp mediu acces
	double Tma = STa / NS;
	cout << "Timpul mediu de acces este: " << Tma << "ms" << endl;
	int d;
	cin >> d;
}