Submission #378543

#	Time	Username	Problem	Language	Result	Execution time	Memory
378543		8e7	Chessboard (IZhO18_chessboard)	C++14	70 / 100	204 ms	2664 KiB

chessboard

//Challenge: Accepted
#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>
#define ll long long
#define maxn 100005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
using namespace std;
struct rect{
	int x1, y1, x2, y2;
	rect() {
		x1 = 0, y1 = 0, x2 = 0, y2 = 0;
	}
	rect(int a, int b, int c, int d) {
		x1 = a, y1 = b, x2 = c, y2 = d;
	}
};
vector<rect> v;

ll solve(ll n, ll len) {
	ll val = 0, block = n / len;
	for (int i = 0;i < block;i++) {
		val += len * len * (block / 2 + (block % 2 && i % 2 ? 1 : 0));
	}
	for (rect a:v) {
		val += (a.x1 / len + a.y1 / len) % 2 ? -1 : 1;
	}
	val = min(val, n * n - val);
	//cout << len << " " << val << endl;
	return val;
}
int main() {
	io
	ll n, k;
	cin >> n >> k;
	for (int i = 0;i < k;i++) {
		ll x1, y1, x2, y2;
		cin >> x1 >> y1 >> x2 >> y2;
		x1--, y1--, x2--, y2--;
		v.push_back(rect(x1, y1, x2, y2));
	}
	ll ans = 1LL<<60;
	for (ll i = 1;i * i <= n;i++) {
		if (n % i == 0) {
			ans = min(ans, solve(n, i));
			if (i * i != n && i != 1) {
				ans = min(ans, solve(n, n / i));
			}
		}
	}
	cout << ans << endl;
}
/*
2 0

6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6
 */

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