Submission #91831

#	Time	Username	Problem	Language	Result	Execution time	Memory
91831		emil_physmath	Chessboard (IZhO18_chessboard)	C++14	100 / 100	1747 ms	5880 KiB

chessboard

#include <iostream>
#include <stdio.h>
using namespace std;
const long long MAXK=100005;
 
long long mini[MAXK], maxi[MAXK], minj[MAXK], maxj[MAXK];
 
long long NumWhite(long long, long long, long long, long long, long long cellLen);
long long FindAns(long long n, long long k, long long cellLen);
int main()
{
	long long n, k;
	cin>>n>>k;
	for (long long i=0; i<k; i++)
		scanf("%lld%lld%lld%lld", mini+i, minj+i, maxi+i, maxj+i);
	long long ans=n*n;
	for (long long cellLen=1LL; cellLen*cellLen<=n; cellLen++)
		if (n%cellLen==0)
		{
			ans=min(ans, FindAns(n, k, cellLen));
			ans=min(ans, FindAns(n, k, n/cellLen));
		}
	cout<<ans<<'\n';
 
	char I;
	cin >> I;
	return 0;
}
 
long long FindAns(long long n, long long k, long long cellLen)
{
	if (cellLen>=n) return n*n;
	long long shouldWhite=0, shouldBlack=0, isBlack=0;
	for (long long i=0; i<k; i++)
	{
		shouldWhite+=NumWhite(mini[i], minj[i], maxi[i], maxj[i], cellLen);
		isBlack+=(maxi[i]-mini[i]+1LL)*(maxj[i]-minj[i]+1LL);
	}
	shouldBlack=(n*n-NumWhite(1LL, 1LL, n, n, cellLen))-(isBlack-shouldWhite);
	return min(shouldWhite+shouldBlack, n*n-(shouldWhite+shouldBlack));
}
long long NumWhite(long long mini, long long minj, long long maxi, long long maxj, long long len)
{
	if (!mini) mini=1LL;
	if (!minj) minj=1LL;
	if (mini==1LL && minj==1LL)
	{
		long long ans=0, i=maxi, j=maxj;
		ans+=len*len*(((i/len)*(j/len)+1LL)/2LL);
		if ((i/len)%2LL)
			ans+=(i%len)*((j/len)/2LL)*len;
		else
			ans+=(i%len)*((j/len+1LL)/2LL)*len;
		if ((j/len)%2LL)
			ans+=(j%len)*((i/len)/2LL)*len;
		else
			ans+=(j%len)*((i/len+1LL)/2LL)*len;
		if ((i/len)%2LL==(j/len)%2LL)
			ans+=(i%len)*(j%len);
		return ans;
	}
	return NumWhite(1LL, 1LL, maxi, maxj, len)-
		NumWhite(1LL, 1LL, maxi, minj-1LL, len)-NumWhite(1LL, 1LL, mini-1LL, maxj, len)+
		NumWhite(1LL, 1LL, mini-1LL, minj-1LL, len);
}
//#include <iostream>
//#include <stdio.h>
//#include <set>
//using namespace std;
//const long long MAXK=1LL00005;
//
//long long mini[MAXK], maxi[MAXK], minj[MAXK], maxj[MAXK];
//
//bool IsWhite(long long, long long);
//long long FindAns(long long n, long long k);
//int main()
//{
//	long long n, k;
//	cin>>n>>k;
//	for (long long i=0; i<k; i++)
//		scanf("%lld%lld%lld%lld", mini+i, minj+i, maxi+i, maxj+i);
//	cout<<FindAns(n, k)<<'\n';
//
//	char I;
//	cin >> I;
//	return 0;
//}
//
//long long FindAns(long long n, long long k)
//{
//	long long shouldWhite=0, shouldBlack=(n*n)/2LL;
//	for (long long i=0; i<k; i++)
//    {
//		if (IsWhite(maxi[i], maxj[i]))
//			shouldWhite++;
//      	else
//          	shouldBlack--;
//	}
//	return min(1LLLL+shouldWhite+shouldBlack, n*n-(shouldWhite+shouldBlack));
//}
//
//bool IsWhite(long long i, long long j)
//{
//	return ((i+j)%2LL==0);
//}

Compilation message (stderr)

chessboard.cpp: In function 'int main()':
chessboard.cpp:15:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld%lld%lld", mini+i, minj+i, maxi+i, maxj+i);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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