| # | Time | Username | Problem | Language | Result | Execution time | Memory | 
|---|---|---|---|---|---|---|---|
| 168969 | cormac | Chessboard (IZhO18_chessboard) | C++14 | 0 ms | 0 KiB | 
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
using ll = long long;
using bk = tuple<ll, ll, ll, ll, ll>;
ll INF = 1LL << 60;
ll count1d(ll x, ll w, ll k) {
    ll sx = k * ((x / k) + (x % k != 0));
    ll ex = (x + w) / k * k;
    if (ex < sx) return w;
    ll m = (ex - sx);
    return (sx - x) + (x + w - ex) * ((sx ==x) != (m/k%2==1)) + (m / k / 2) * k + k * ((m/k)%2 && (sx == x));
}
ll count2d(ll x, ll y, ll w, ll h, ll k) {
    ll r = count1d(x, w, k); 
    if ((x / k + y / k) % 2 == 1) r = w - r;
    ll c = count1d(y, h, k);
    return  r * c + (w-r) * (h-c);
}
int main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    ll N, K, A, tA;
    cin >> N >> K;
    A = N*N;
    
    
    vector<bk> blocks (K);
    F0R(i, K) {
        ll x, y, w, h;
        cin >> x >> y >> w >> h;
        w-=x; h-=y;
        --x; --y; ++w; ++h; tA += w * h;
        blocks[i] = make_tuple(w*h, y, x, h, w);
    }
    sort(blocks.begin(), blocks.end());
    ll best = INF;
    ROF(i, 1, N) {
        if (N % i != 0) continue;
        ll cA = tA;
        
        ll c1 = count2d(0, 0, N, N, i);
        ll c2 = A - c1;
        for (bk block : blocks) {
            ll x, y, w, h, a;
            tie(a, x, y, w, h) = block;    
            ll overlap = count2d(x, y, w, h, i);
            cA -= a;
            c1 -= overlap;
            c1 += a - overlap;
            c2 += overlap;
            c2 -= a - overlap;
            if (c2 - cA >= best && c1 - cA >= best)
        }
        best = min(best, c1);
        best = min(best, c2);
    }
    
    cout << best << endl; 
}
