Submission #155160

#	Time	Username	Problem	Language	Result	Execution time	Memory
155160		srvlt	Chessboard (IZhO18_chessboard)	C++14	47 / 100	2058 ms	5220 KiB

chessboard

//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse2,avx")
#include <bits/stdc++.h>
#define ll long long
#define db long double
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define fi first
#define se second
#define mp make_pair
#define endl "\n"
//#define int long long
using namespace std;

void dout() {
    cerr << endl;
}

template <typename Head, typename... Tail>
void dout(Head H, Tail... T) {
    cerr << H << ' ';
    dout(T...);
}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e5 + 3;
const ll inf = 1e18;

struct rect {
    int x = 0, y = 0, x2 = 0, y2 = 0;
};

int k, p[2][N];
ll n, ans = inf, A, Z, S, W, B, L;
vector <rect> v;

int color(int x, int y) {
    int z = (x - 1) / A;
    int w = (y - 1) / A;
    return ((z + w + Z) & 1);
}

int num(int x) {
    int z = (x - 1) / A;
    return (z & 1);
}

ll getL() {
    int x = n / A;
    ll a = ((x + 1) / 2) * A * A;
    ll b = (x / 2) * A * A;
    ll res = ((x + 1) / 2) * a + (x / 2) * b;
    if (Z == 0) {
        return res;
    }   else {
        return n * n - res;
    }
}

ll getval(int x, int a, int b) {
    if (x < 1) {
        return 0;
    }
    ll res = 0;
    int last = ((x - 1) / A) * A + 1;
    if (num(last) == 0) {
        res += (x - last + 1) * a;
    }   else {
        res += (x - last + 1) * b;
    }
    int q = (last - 1) / A;
    res += ((q + 1) / 2) * A * a;
    res += (q / 2) * A * b;
    return res;
}

ll getans() {
    for (int i = 1; i <= n; i++) {
        p[0][i] = p[0][i - 1];
        p[1][i] = p[1][i - 1];
        if (color(i, 1)) {
            p[0][i]++;
        }   else {
            p[1][i]++;
        }
    }
    ll res = 0;
    for (auto i : v) {
        int x = i.x, y = i.y, x2 = i.x2, y2 = i.y2;
        int v1 = p[0][x2] - p[0][x - 1];
        int v2 = p[1][x2] - p[1][x - 1];
        res += getval(y2, v1, v2) - getval(y - 1, v1, v2);
    }
    return res;
}

void solve(int tc) {
    cin >> n >> k;
    for (int i = 0; i < k; i++) {
        rect tmp;
        cin >> tmp.x >> tmp.y >> tmp.x2 >> tmp.y2;
        S += (ll)(tmp.x2 - tmp.x + 1) * (tmp.y2 - tmp.y + 1);
        v.pb(tmp);
    }
    vector <int> factors = {};
    for (int i = 1; i < n; i++) {
        if (n % i == 0) {
            factors.pb(i);
        }
    }
    for (auto i : factors) {
        A = i;
        for (int j = 0; j < 2; j++) {
            Z = j;
            L = getL();
            W = getans();
            B = L - (S - W);
            ans = min(ans, W + B);
        }
    }
    cout << ans;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
    int tc = 1;
//    cin >> tc;
    for (int i = 0; i < tc; i++) {
        solve(i);
//        cleanup();
    }
}

• Subtask 1: 8 / 8
• Subtask 2: 8 / 8
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 0 / 23
• Subtask 6: 0 / 30