Submission #43747

#	Time	Username	Problem	Language	Result	Execution time	Memory
43747		nickyrio	Chessboard (IZhO18_chessboard)	C++14	70 / 100	2118 ms	262144 KiB

chessboard

#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define DEBUG(x) { cerr << #x << '=' << x << endl; }
#define Arr(a, l, r) { cerr << #a << " = {"; FOR(_, l, r) cerr << ' ' << a[_]; cerr << "}\n"; }
#define N 1001000
#define pp pair<int, int>
#define endl '\n'
#define IO ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define taskname ""
#define bit(S, i) (((S) >> (i)) & 1)
using namespace std;
long long n, k, xx1[N], xx2[N], xy1[N], xy2[N];

long long cal(int l, int color, int x1, int y1, int x2, int y2) {
    if (x2 < x1 || y2 < y1) return 0;
    int mx1 = (x1 - 1 + l) / l * l, mx2 = (x2 + 1) / l * l - 1;
    int my1 = (y1 - 1 + l) / l * l, my2 = (y2 + 1) / l * l - 1;
    if (x1 / l == x2 / l) {
        if (y1 / l == y2 / l) {
            if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * (x2 - x1 + 1) * (y2 - y1 + 1);
            return 1ll * (x2 - x1 + 1) * (y2 - y1 + 1);
        }
        if (my1 == y1 && my2 == y2) {
            int sz = (y2 + 1 - y1) / l;
            if (sz % 2 == 0) return 0;
            if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * (x2 - x1 + 1) * l;
            return 1ll * (x2 - x1 + 1) * l;;
        }
        return cal(l, color, x1, y1, x2, my1 - 1)
            +  cal(l, color, x1, my1, x2, my2)
            +  cal(l, color, x1, my2 + 1, x2, y2);
    }
    if (mx1 == x1 && mx2 == x2 && y1 == my1 && y2 == my2) {
        int sz = (y2 + 1 - y1) / l * (x2 + 1 - x1) / l;
        if (sz % 2 == 0) return 0;
        if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * l * l;
        return l * l;    
    }
    return cal(l, color, x1, y1, mx1 - 1, y2)
        + cal(l, color, mx1, y1, mx2, y2) 
        + cal(l, color, mx2 + 1, y1, x2, y2);
}
long long solve(int l, int color) {// color = 0 -> Top-left is black
    long long ans = ((1ll * (n / l) * (n / l) + 1 - color) / 2) * l * l ;
    /*REP(i, k) {
        if (color ^ (((xx1[i] / l) % 2) == (xy1[i] / l) % 2)) ans--;
        else ans++;
    }*/
    REP(i, k) {
        ans += cal(l, color, xx1[i], xy1[i], xx2[i], xy2[i]);
    }
    return ans;
} 
int main() {
    #ifdef NERO
    freopen("test.inp","r",stdin);
    freopen("test.out","w",stdout);
    clock_t stime = clock();
    #endif //NERO
    IO;
    cin >> n >> k;
    long long ans = 1e10;
    REP(i, k) cin >> xx1[i] >> xy1[i] >> xx2[i] >> xy2[i];
    REP(i, k) xx1[i]--,xx2[i]--,xy1[i]--,xy2[i]--;
    FOR(i, 1, sqrt(n)) if (n % i == 0) {
        ans = min(ans, solve(i, 0));
        ans = min(ans, solve(i, 1));
        if (i != 1) ans = min(ans, solve(n / i, 0));
        if (i != 1) ans = min(ans, solve(n / i, 1));
    }
    cout << ans;
    #ifdef NERO
    clock_t etime = clock();
    cerr << "Execution time: " << (etime - stime) / CLOCKS_PER_SEC * 1000 << " ms.";
    #endif // NERO
}

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