Submission #523575

#	Time	Username	Problem	Language	Result	Execution time	Memory
523575		RaresFelix	Chessboard (IZhO18_chessboard)	C++17	70 / 100	952 ms	4980 KiB

chessboard

#include <iostream>
#include <climits>
#include <tuple>
#include <vector>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#define MN 167171

using namespace std;
using ll = long long;
ll n, k;
tuple<int, int, int, int> R[MN];
ll P[MN], D[MN];
ll P2[MN], D2[MN];
static inline ll calc(ll a, ll b, ll l) {
    if(P[a] == 0 && P[b] == 0)
        return ((D[a] * D[b] + 1) >> 1) * l * l;
    if(P[a]) {
        ll nrseg;
        if((D[a] & 1) == 0) {
            if(P2[b] <= l) nrseg = D2[b] * l + P2[b];
            else nrseg = (D2[b] + 1) * l;
        } else {
            if(P2[b] <= l) nrseg = D2[b] * l;
            else nrseg = (D2[b] - 1) * l + P2[b];
        }
        return calc(a - P[a], b, l) + P[a] * nrseg;
    }
    return calc(b, a, l);
}
ll sol(ll l) {
    for(int i = 1; i <= n; ++i) {
        D[i] = D[i-1];
        P[i] = P[i-1] + 1;
        if(P[i] == l) ++D[i], P[i] = 0;
        D2[i] = D2[i-1];
        P2[i] = P2[i-1] + 1;
        if(P2[i] == (l << 1)) ++D2[i], P2[i] = 0;
    }
    ll arie = ((n / l) * (n / l) + 1) / 2 * l * l, selec;
    for(int i = 1; i <= k; ++i) {
        auto &[a, b, c, d] = R[i];
        selec = calc(c, d, l) + calc(a-1, b-1, l) - calc(c, b-1, l) - calc(a-1, d, l);
        arie += (c - a + 1) * (d - b + 1) - 2 * selec;
    }
    return min(arie, 1ll * n * n - arie);
}
int main() {
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    cin >> n >> k;
    for(int i = 1, a, b, c, d; i <= k; ++i)
        cin >> a >> b >> c >> d, R[i] = make_tuple(a, b, c, d);
    ll re = LLONG_MAX;
    for(int i = 1; i < n; ++i)
        if(n % i == 0) re = min(re, sol(i));
    cout << re << "\n";
    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