Submission #90547

#	Time	Username	Problem	Language	Result	Execution time	Memory
90547		HardNut	Chessboard (IZhO18_chessboard)	C++17	100 / 100	1071 ms	39056 KiB

chessboard

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 5;
const long long INF = 1e18 + 5;
const int MAXN = 1e6;
const int base = 317;

typedef long long ll;

const ll bs = 1e5 + 1;
const ll mod = 998244353;

#define int ll

ll ans = INF, n, k, xx[N], yy[N], xx1[N], yy1[N];

int fnd(int cor, int x) {
    if (cor <= 0)
        return 0;
    int res = (cor / x) / 2 * x;
    if ((cor / x) % 2)
    res += cor % x + 1;
    return res;
}

ll calc(ll x) {
    ll res1 = 0, res2 = 0;
    for (int i = 1; i <= k; i++) {
        int b1 = fnd(xx1[i], x) - fnd(xx[i] - 1, x),
        w1 = (xx1[i] - xx[i] + 1) - b1,
        b2 = fnd(yy1[i], x) - fnd(yy[i] - 1, x),
        w2 = (yy1[i] - yy[i] + 1) - b2;
        int x1 = xx[i] / x, y1 = yy[i] / x;
        if (x1 % 2) {
            swap(b2, w2);
        }
        if (y1 % 2) {
            swap(b1, w1);
        }
        if (x1 % 2 == y1 % 2) {
            res1 += b1 * b2 + w1 * w2;
            res2 += (b1 * w2 + w1 * b2);
        } else {
            res1 += b1 * w2 + w1 * b2;
            res2 += b1 * b2 + w1 * w2;
        }
    }
    ll c1 = (n / x) * (n / x) / 2 * x * x;
    ll c2 = n * n - c1;
    return min(c1 - res2 + res1, c2 - res1 + res2);
}

main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= k; i++) {
        cin >> xx[i] >> yy[i] >> xx1[i] >> yy1[i];
        xx[i]--;
        yy[i]--;
        xx1[i]--;
        yy1[i]--;
    }
    for (int i = 1; i <= sqrt(n); i++) {
        if (n % i == 0) {
            ans = min(ans, calc(i));
            if (i != 1)
                ans = min(ans, calc(n / i));
        }
    }
    cout << ans;
    return 0;
}
/*

*/

Compilation message (stderr)

chessboard.cpp:55:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

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