Submission #68105

#	Time	Username	Problem	Language	Result	Execution time	Memory
68105		MatheusLealV	Chessboard (IZhO18_chessboard)	C++17	100 / 100	1169 ms	47424 KiB

chessboard

#include <bits/stdc++.h>
#define N 100050
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;

ll n, k, x[N], y[N], xf[N], yf[N];

long long ans = (2000000000000000000ll);

vector<ll> d;

inline ll conta(ll x, ll y, ll r)
{
	x ++, y ++;

	ll tx = (x/r), ty = (y/r);

	int rx = (tx % 2 == 0 ? 1 : 0), ry = (ty % 2 == 0 ? 1 : 0);

	ll xo = ((tx + 1)/2)*r + (rx ? x % r : 0);

	ll xi = (x - xo);

	ll yo = ((ty + 1)/2)*r + (ry ? y % r : 0);

	ll yi = (y - yo);

	return xo*yo + xi*yi;
}

inline ll custo(ll xi, ll yi, ll xii, ll yii, ll r)
{
	ll C = conta(xii, yii, r) - conta(xi - 1, yii, r) - conta(xii, yi - 1, r) + conta(xi - 1, yi - 1, r);

	return C;
}

int main()
{
	ios::sync_with_stdio(false); cin.tie(0);

	cin>>n>>k;

	for(int i = 1; i <= k; i++) cin>>x[i]>>y[i]>>xf[i]>>yf[i];

	for(int i = 1; i <= k; i++) 
	{
		x[i] --, y[i] --, xf[i] --, yf[i] --;

		if(x[i] > xf[i]) swap(x[i], xf[i]);

		if(y[i] > yf[i]) swap(y[i], yf[i]);
	}

	for(int i = 1; i <= sqrt(n); i++)
	{
		if((n % i) != 0) continue;

		d.push_back(i);

		if(i != n/i) d.push_back(n/i);
	}

	for(auto r: d)
	{	
		ll pretocerto = 0, pretoerrado = 0, tot;

		if(r == n) continue;

		tot = ( ((n/r) * (n/r)) + 1LL)/2LL;

		tot = (tot * r * r); 

		for(int i = 1; i <= k; i++)
		{
			ll S = custo(x[i], y[i], xf[i], yf[i], r);

			//cout<<"CUSTO "<<x[i]<<" "<<y[i]<<" "<<xf[i]<<" "<<yf[i]<<" = "<<S<<"\n";

			pretocerto += S;

			pretoerrado += (xf[i] - x[i] + 1) * (yf[i] - y[i] + 1) - S;
		}

		ans = min(ans, tot - pretocerto + pretoerrado);

		tot = ( ((n/r) * (n/r)))/2LL;

		tot = (tot * r * r); 

		ans = min(ans, tot + pretocerto - pretoerrado);

	}

	cout<<ans<<"\n";
}

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