Submission #155381

#	Time	Username	Problem	Language	Result	Execution time	Memory
155381		srvlt	Chessboard (IZhO18_chessboard)	C++14	100 / 100	1975 ms	5904 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());
typedef pair <int, int> pii;
const int N = 1e5 + 7, inf = 1e18;
int n, k, x[N], y[N], x2[N], y2[N], ans = inf;
int A, S;

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

int open(int x) {
    if (x == 0) {
        return 0;
    }
    return (x - 1) / A + 1;
}

int close(int x) {
    return x / A;
}

int last_close(int x) {
    return close(x) * A;
}

int next_close(int x) {
    int tmp = last_close(x);
    if (x == tmp) {
        return x;
    }
    return tmp + A;
}

int last_open(int x) {
    return (open(x) - 1) * A + 1;
}

int next_open(int x) {
    int tmp = last_open(x);
    if (x == tmp) {
        return x;
    }
    return tmp + A;
}

pii get_colors(int l, int r) {
    int blocks = close(r) - open(l - 1);
    int a = 0, b = 0;
    if (blocks > 0) {
        if (num(l) == 0) {
            int len = next_open(l) - l;
            a += len;

            if (len > 0) {
                a += (blocks / 2) * A;
                b += ((blocks + 1) / 2) * A;
            }   else {
                a += ((blocks + 1) / 2) * A;
                b += (blocks / 2) * A;
            }
        }   else {
            int len = next_open(l) - l;
            b += len;

            if (len > 0) {
                a += ((blocks + 1) / 2) * A;
                b += (blocks / 2) * A;
            }   else {
                a += (blocks / 2) * A;
                b += ((blocks + 1) / 2) * A;
            }
        }
        if (num(r) == 0) {
            a += r - last_close(r);
        }   else {
            b += r - last_close(r);
        }
    }   else {
        if (num(l) == 0) {
            a += next_open(l) - l;
        }   else {
            b += next_open(l) - l;
        }
        if (num(r) == 0) {
            a += r - next_open(l) + 1;
        }   else {
            b += r - next_open(l) + 1;
        }
    }
    return {a, b};
}

pii get_squares() {
    int even = (n / A) / 2, odd = ((n / A) + 1) / 2;
    int a = even * odd + odd * even;
    int b = odd * odd + even * even;
    return {a * A * A, b * A * A};
}

int get_color(int x, int y, int z) {
    return (num(x) + num(y) + z) & 1;
}

int get_ans() {
    int res0 = 0, res1 = 0;
    for (int i = 0; i < k; i++) {
        pii t1 = get_colors(y[i], y2[i]);
        pii t2 = get_colors(x[i], x2[i]);
        int a = t2.fi, b = t2.se;
        int c = t1.fi, d = t1.se;

        res0 += a * c + b * d;
        res1 += b * c + a * d;
    }
    pii tmp = get_squares();
    return min(tmp.se - S + 2LL * res1, tmp.fi - S + 2LL * res0);
}

void solve(int tc) {
    cin >> n >> k;
    for (int i = 0; i < k; i++) {
        cin >> x[i] >> y[i] >> x2[i] >> y2[i];
        S += (x2[i] - x[i] + 1) * (y2[i] - y[i] + 1);
    }
    for (int i = 1; i < n; i++) {
        if (n % i == 0) {
            A = i;
            ans = min(ans, get_ans());
        }
    }
    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: 23 / 23
• Subtask 6: 30 / 30