Submission #495154

#	Time	Username	Problem	Language	Result	Execution time	Memory
495154		Nalrimet	Chessboard (IZhO18_chessboard)	C++17	70 / 100	253 ms	4244 KiB

chessboard

#include<bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define pb push_back
#define ll long long

const int N = 1e5 + 5;
const ll inf = 1e18;


long long n, k, x[N], y[N], cnt1, cnt2, m1, m2, ans = inf, b1, b2, s;
vector<long long> v;

int main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> k;

    for(ll i = 1; i * i <= n; ++i){
        if(n % i == 0){
            v.pb(i);
            if(i != n / i) v.pb(n / i);
        }
    }

    for(ll i = 1, x1, y1; i <= k; ++i){
        cin >> x[i] >> y[i];

        cin >> x1 >> y1;
    }

    for(auto to : v){
        if(to == n) continue;
        cnt1 = 0;
        cnt2 = 0;
        for(ll i = 1; i <= k; ++i){
            b1 = (x[i] + to - 1) / to;
            b2 = (y[i] + to - 1) / to;
            if(b1 % 2) {
                if(b2 % 2) cnt1++;
                else cnt2++;
            }
            else {
                if(b2 % 2) cnt2++;
                else cnt1++;
            }
        }
//        cout << to << ' ' << cnt1 << ' ' << cnt2 << '\n';
        s = n / to;
//        cout << s << '\n';
        m1 = (s + 1) / 2 * ((s + 1) / 2) + (s / 2) * (s / 2);
        m2 = s * s - m1;
//        cout << m1 << ' ' << m2 << '\n';
        m1 *= to * to;
        m2 *= to * to;
//        cout << m1 << ' ' << m2 << '\n';
        ans = min(ans, min(m1 - cnt1 + cnt2, m2 - cnt2 + cnt1));
//        cout << m1 - cnt1 + cnt2 << '\n' << m2 - cnt2 + cnt1 << '\n';
    }

    cout << ans;

    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