Submission #168456

#	Time	Username	Problem	Language	Result	Execution time	Memory
168456		achibasadzishvili	Chessboard (IZhO18_chessboard)	C++14	70 / 100	344 ms	3356 KiB

chessboard

#include <bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
#define mp make_pair
using namespace std;
ll ans,n,k,x[200005],y[200005];
void solve(ll t){
    if(t == n)return;
    ll raod = 0;
    for(int i=1; i<=k; i++)
        if((x[i] / t + y[i] / t) % 2 == 0)raod++;
    if((n / t) % 2 == 0){
        raod = max(raod , k - raod);
        ans = min(ans , ((n * n) / 2) - raod + k - raod);
    }
    else{
        ll fir = (((n/t)*(n/t))/2 + 1) * (t * t) - raod + (k - raod);
        ll sec = (((n/t)*(n/t))/2) * (t * t) - (k - raod) + raod;
        ans = min(ans , min(fir , sec));
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin >> n >> k;

    for(int i=1; i<=k; i++){
        cin >> x[i] >> y[i] >> x[i] >> y[i];
        x[i]--;
        y[i]--;
    }


    ans = n * n;

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