Submission #378517

#	Time	Username	Problem	Language	Result	Execution time	Memory
378517		jass921026	Chessboard (IZhO18_chessboard)	C++14	39 / 100	74 ms	1132 KiB

chessboard

#include<bits/stdc++.h>
using namespace std;
#define jizz ios_base::sync_with_stdio(false);cin.tie(NULL);
typedef long long ll;
typedef pair<int,int> pii;
#define F first
#define S second
#define FOR(i,n) for(int i=0;i<n;i++)
#define FOO(i,a,b) for(int i=a;i<=b;i++)
#define OOF(i,a,b) for(int i=a;i>=b;i--)
#define ALL(x) (x).begin(),(x).end()
#define pb push_back
#define mkp make_pair
const int MAXN=1E5+10;
int n, k;
pii point[MAXN];
ll solve(int i){
    ll col=i*i*(((n/i)*(n/i)+1)/2), rights=0, wrongs=0;
    for(int j=0;j<k;j++){
        if((point[j].F/i)%2==(point[j].S/i)%2){
            rights++;
        } else{
            wrongs++;
        }
    }
    return min(col-rights+wrongs,(n*n-col)-wrongs+rights);
}
int main(){ jizz
    cin>>n>>k;
    FOR(i,k){
        int x1, y1, x2, y2;
        cin>>x1>>y1>>x2>>y2;
        point[i]=mkp(x1-1,y1-1);
    }
    ll ans=n*n;
    for(int i=1;i*i<=n;i++){
        if(n%i==0){
            ans=min(ans,solve(i));
            if(i>1) ans=min(ans,solve(n/i));
        }
    }
    cout<<ans<<"\n";
    return 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: 0 / 8
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 0 / 23
• Subtask 6: 0 / 30