Ruudukko

#include <string>
#include <iostream>
#include <vector>

int main()
{
	int n, m;
	std::cin >> n >> m;
	std::cin.ignore();

	std::vector<int> ruudukko(n * n);

	for (int i = 0; i < m; ++i)
	{
		int a, b, c, d;
		std::cin >> a >> b >> c >> d;
		a--; b--; c--; d--;

		for (int i = 0; i < c - a + 1; ++i)
		{
			ruudukko[(a + i) * n + b]++;
			ruudukko[(a + i) * n + d + 1]++;
		}
	}

	std::string printtaus;
	printtaus.reserve(n * n + n);
	char merkki = '.';
	for (int i = 0; i < n * n; ++i)
	{
		if (i % n == 0 && i != 0)
			printtaus += '\n';

		int ruutu = ruudukko[i];

		if (ruutu % 2 == 1)
			merkki = merkki == '.' ? '#' : '.';
		printtaus += merkki;
	}
	std::cout << printtaus << std::endl;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 2, 3

Verdict: ACCEPTED

Test 4

Group: 3

Verdict: ACCEPTED

Test 5

Group: 3

Verdict: TIME LIMIT EXCEEDED