Submission #518782

#	Time	Username	Problem	Language	Result	Execution time	Memory
518782		spike1236	Chessboard (IZhO18_chessboard)	C++14	100 / 100	616 ms	2832 KiB

chessboard

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long
#define ld long double
#define all(_v) _v.begin(), _v.end()
#define sz(_v) (int)_v.size()
#define pii pair <int, int>
#define pll pair <ll, ll>
#define veci vector <int>
#define vecll vector <ll>

const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
const double PI = 3.1415926535897932384626433832795;
const double eps = 1e-9;
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;

const int MAXN = 2e5 + 10;
ll n;
ll cnt[MAXN];

ll get(ll r, ll k) {
    ll nr = r - r % k;
    ll bl = nr / k;
    ll cnt = (bl + 1) / 2 * k;
    if(bl % 2 == 0) cnt += r - nr;
    return cnt;
}

void solve() {
    int k;
    cin >> n >> k;
    vecll dv;
    dv.pb(1);
    for(ll i = 2; i * i <= n; ++i) {
        if(n % i == 0) {
            dv.pb(i);
            if(i * i != n) dv.pb(n / i);
        }
    }
    sort(all(dv));
    for(auto i : dv) {
        ll cnt1 = get(n, i);
        cnt[i] = cnt1 * i * (((n / i) + 1) / 2) + (n - cnt1) * i * (n / i - (((n / i) + 1) / 2));
    }
    for(int rect = 1; rect <= k; ++rect) {
        ll x1, y1, x2, y2;
        cin >> x1 >> y1 >> x2 >> y2;
        for(auto i : dv) {
            ll row_cnt[2];
            row_cnt[1] = get(x2, i) - get(x1 - 1, i);
            row_cnt[0] = x2 - x1 + 1 - row_cnt[1];
            ll col_cnt[2];
            col_cnt[1] = get(y2, i) - get(y1 - 1, i);
            col_cnt[0] = y2 - y1 + 1 - col_cnt[1];
            cnt[i] -= row_cnt[1] * col_cnt[1];
            cnt[i] -= row_cnt[0] * col_cnt[0];
            cnt[i] += row_cnt[0] * col_cnt[1];
            cnt[i] += row_cnt[1] * col_cnt[0];
        }
    }
    ll ans = 4e18;
    for(auto i : dv) ans = min(ans, min(cnt[i], n * n - cnt[i]));
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int CNT_TESTS = 1;
    ///cin >> CNT_TESTS;
    for(int NUMCASE = 1; NUMCASE <= CNT_TESTS; ++NUMCASE) {
        solve();
        if(NUMCASE != CNT_TESTS) cout << '\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: 30 / 30