Submission #237229

#	Time	Username	Problem	Language	Result	Execution time	Memory
237229		kshitij_sodani	Chessboard (IZhO18_chessboard)	C++17	70 / 100	379 ms	4584 KiB

chessboard

#include <bits/stdc++.h>
using namespace std;
typedef int64_t llo;
#define mp make_pair
#define pb push_back
#define a first
#define b second
llo n,k;
llo aa,bb,cc,dd;
vector<pair<llo,llo>> cur;
llo check(llo nn){
	if(nn==n){
		return n*n;
	}
	llo co;
	if((n/nn)%2==0){
		co=(n*n)/2;
	}
	else{
		co=(n*n-nn*nn)/2;
	}
	//cout<<co<<":";
	for(auto i:cur){
		if((i.a/nn+i.b/nn)%2==1){
			co-=1;
		}
		else{
			co+=1;
		}
	}
	llo co2;
	if((n/nn)%2==0){
		co2=(n*n)/2;
	}
	else{
		co2=(n*n+nn*nn)/2;
	}
//	cout<<co2<<endl;
	for(auto i:cur){
		if((i.a/nn+i.b/nn)%2==0){
			co2-=1;
		}
		else{
			co2+=1;
		}
	}
//	cout<<nn<<","<<co<<","<<co2<<endl;
	return min(co,co2);
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin>>n>>k;

	for(llo i=0;i<k;i++){
		cin>>aa>>bb>>cc>>dd;
		aa-=1;
		bb-=1;
		cur.pb({aa,bb});
	}
	llo ans=n*n;
	for(llo i=1;i*i<=n;i++){
		if(n%i==0){
			ans=min(ans,check(i));
			ans=min(ans,check(n/i));
		}
	}
	cout<<ans<<endl;



	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