Submission #334380

#	Time	Username	Problem	Language	Result	Execution time	Memory
334380		amunduzbaev	Chessboard (IZhO18_chessboard)	C++14	8 / 100	23 ms	1132 KiB

chessboard

#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define ll long long 
#define ld long double 
#define pii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define prc(n) fixed << setprecision(n)
#define fastios ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pi acos(-1);
const int inf = 1e9+7;
const int N = 1e3+5;

int x[N][N], pref[N][N];

ll ans, n, k;

void check(ll size){
	//cout<<size<<"\n";
	ll cnt = 0;
	ll q = size * size;
	for(int i=size;i<=n;i+=size){
		for(int j=size;j<=n;j+=size){
			if(((j/size) + (i/size))%2 == 1) cnt += q - (pref[i][j] - pref[i - size][j] - pref[i][j - size] + pref[i - size][j - size]);
			else cnt += (pref[i][j] - pref[i - size][j] - pref[i][j - size] + pref[i - size][j - size]);
		//	cout<<cnt<<" ";
		}
	}
	ans = min((ll)cnt, ans);
	cnt = 0;
	for(int i=size;i<=n;i+=size){
		for(int j=size;j<=n;j+=size){
			if(((j/size) + (i/size))%2 == 0) cnt += q - (pref[i][j] - pref[i - size][j] - pref[i][j - size] + pref[i - size][j - size]);
			else cnt += (pref[i][j] - pref[i - size][j] - pref[i][j - size] + pref[i - size][j - size]);
		//	cout<<cnt<<" ";
		}//cout<<"\n";
	}
	//cout<<cnt<<"\n";
	ans = min((ll)cnt, ans);
}

void solve(){
	fastios
	ans = inf;
	cin>>n>>k;
	if(k == 0){
		ans = n*n/2;
		for(int i=2;i*1ll*i<=n;i++){
			if(n % i == 0){
				ll num = n/i;
				ans = min(ans, num * num /2 * i * i);
				num = i;
				ans = min(ans, num * num /2 * (n/i) * (n/i));
			}
		}
		cout<<ans<<"\n";
		return;
	}
	bool ok = 1;
	for(int i=2;i * 1ll * i<=n;i++){
		if(n % i == 0) ok = 0;
	}
	if(ok){
		int ono = 0, one = 0;
		for(int i=0;i<k;i++){
			int a, b, c, d;
			cin>>a>>b>>c>>d;
			if((a + b) %2 == 0) one++;
			else ono++;
		}
		//int f = , s;
		//cout<<min(ono)
		cout<<min((n*n+1)/2 - ono + one, n*n/2 - one + ono)<<"\n";
		return;
	}
	for(int i=0;i<k;i++){
		int a, b, c, d;
		cin>>a>>b>>c>>d;
		x[a][b] = 1;
	}
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			pref[i][j] = pref[i-1][j] + pref[i][j-1] + x[i][j] - pref[i-1][j-1]; 
		}
	}
	for(int i=1;i * 1ll * i<=n;i++){
		if(n % i == 0){
			check(i);
			if(i != 1 && n/i != i) check(n/i);
		}
	}
	cout<<ans;
	return;
}
/*

3 3
1 3 1 3
2 3 3 3
1 1 3 1

5 8
2 1 2 1
3 1 3 1
5 2 5 2
1 5 1 5
2 3 2 3
2 4 2 4
3 3 3 3
4 3 4 3

6 8
1 2 1 2
2 1 2 1
3 3 3 3
3 4 3 4
4 3 4 3
4 4 4 4
3 6 3 6
5 5 5 5

*/
int main(){
	fastios
	int t = 1;
	//cin>>t;
	while(t--) solve();
	return 0;
}

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