Submission #907415

#	Time	Username	Problem	Language	Result	Execution time	Memory
907415		daoquanglinh2007	Chessboard (IZhO18_chessboard)	C++17	70 / 100	159 ms	4388 KiB

chessboard

#include <bits/stdc++.h>
using namespace std;

#define int long long

const int NM = 1e5, inf = 1e18;

int N, K, x[NM+5], y[NM+5], ans = +inf;
int num[2];

void solve(int t){
	num[0] = num[1] = 0;
	for (int i = 1; i <= K; i++){
		int blx = x[i]/t+(x[i]%t > 0), bly = y[i]/t+(y[i]%t > 0);
		num[(blx+bly)%2]++;
	}
	int targ = t*t*(N*N/(t*t)/2);
	ans = min(ans, abs(targ-num[1])+num[0]);
	ans = min(ans, abs(N*N-targ-num[0])+num[1]);
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin >> N >> K;
	for (int i = 1; i <= K; i++){
		cin >> x[i] >> y[i] >> x[i] >> y[i];
	}
	for (int i = 1; i*i <= N; i++)
		if (N%i == 0){
			solve(i);
			if (i > 1) solve(N/i);
		}
	cout << ans;
	return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 8 / 8
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 23 / 23
• Subtask 6: 0 / 30