Submission #492362

#	Time	Username	Problem	Language	Result	Execution time	Memory
492362		Rainbowbunny	Chessboard (IZhO18_chessboard)	C++17	100 / 100	472 ms	4296 KiB

chessboard

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

const int MAXN = 1e5 + 5;

int n, k;
int xl[MAXN], xr[MAXN], yl[MAXN], yr[MAXN];

pair <int, int> Get(int p, int id)
{
    if(p < 0)
    {
        return make_pair(0, 0);
    }
    int seg = p / id + 1;
    int cw = (seg + 1) / 2, cb = seg / 2;
    if(cw == cb)
    {
        return make_pair(cw * id, (cb - 1) * id + p % id + 1);
    }
    else
    {
        return make_pair((cw - 1) * id + p % id + 1, cb * id);
    }
}

long long Solve(int id)
{
    long long tmp = 1ll * (n / id) * (n / id) / 2;
    long long curans = tmp * id * id;
    for(int i = 1; i <= k; i++)
    {
        pair <int, int> AA = Get(xr[i], id), BB = Get(xl[i] - 1, id);
        long long countxw = AA.first - BB.first, countxb = AA.second - BB.second;
        AA = Get(yr[i], id), BB = Get(yl[i] - 1, id);
        long long countyw = AA.first - BB.first, countyb = AA.second - BB.second;
        long long corr = countyw * countxb + countyb * countxw, incorr = countyb * countxb + countyw * countxw;
        curans -= corr;
        curans += incorr;
    }
    return min(curans, 1ll * n * n - curans);
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> k;
    for(int i = 1; i <= k; i++)
    {
        cin >> xl[i] >> yl[i] >> xr[i] >> yr[i];
        xl[i]--;
        yl[i]--;
        xr[i]--;
        yr[i]--;
    }
    long long ans = 1e18;
    for(int i = 1; i < n; i++)
    {
        if(n % i == 0)
        {
            ans = min(ans, Solve(i));
        }
    }
    cout << ans << '\n';
}

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