Submission #906019

#	Time	Username	Problem	Language	Result	Execution time	Memory
906019		rockstar	Chessboard (IZhO18_chessboard)	C++17	100 / 100	404 ms	5724 KiB

chessboard

//#pragma GCC optimize("O3,unroll-loops,inline,fast-math")
//#pragma GCC target("avx,avx2,sse3,ssse3,sse4.1,sse4.2,fma,bmi2,abm,popcnt,mmx,tune=native")

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

#define int ll
#define all(a) a.begin(), a.end()

void solve() {
    int n, k;
    cin >> n >> k;
    vector<array<int, 4>> p(k);
    for (auto &i : p)
        cin >> i[0] >> i[1] >> i[2] >> i[3];
    int res = 1e18;
    auto pref = [](int i, int j, int l) {
        int ii = i / l * l, jj = j / l * l;
        int res = 0;
        if ((ii / l + jj / l) % 2) {
            res += (ii / l) * (jj / l) / 2 * l * l;
            res += ((jj / l) + 1) / 2 * l * (i - ii);
            res += ((ii / l) + 1) / 2 * l * (j - jj);
        } else {
            res += (i - ii) * (j - jj);
            res += ((ii / l) * (jj / l) + 1) / 2 * l * l;
            res += (jj / l) / 2 * l * (i - ii);
            res += (ii / l) / 2 * l * (j - jj);
        }
        return res;
    };
    auto upd = [&](int l) {
        int now = n * n - pref(n, n, l);
        for (auto i : p) {
            int w = pref(i[2], i[3], l) + pref(i[0] - 1, i[1] - 1, l) - pref(i[2], i[1] - 1, l) - pref(i[0] - 1, i[3], l);
            now += w;
            now -= (i[2] - i[0] + 1) * (i[3] - i[1] + 1) - w;
        }
        res = min(res, min(now, n * n - now));
    };
    for (int i = 1; i * i <= n; ++i)
        if (n % i == 0) {
            upd(i);
            if (n / i != i && i != 1)
                upd(n / i);
        }
    cout << res;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
//    cin >> t;
    while (t--)
        solve();
}

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