Submission #1112619

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112619		vjudge1	Chessboard (IZhO18_chessboard)	C++17	100 / 100	224 ms	13128 KiB

chessboard

//Dost SEFEROĞLU
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " << 
#define vi vector<int>
#define all(xx) xx.begin(),xx.end()
#define ps(xxx) cout << (xxx) << endl;
const int N = 5e2+1,inf = 1e16,MOD = 1e9+7; 
 

void solve() { 
    int n,k;
    cin >> n >> k;
    vector<pii> adds[n+2],rems[n+2];
    for (int i=1;i<=k;i++) {
        int x1,y1,x2,y2;
        cin >> x1 >> y1 >> x2 >> y2;
        adds[x1].push_back({y1,y2});
        rems[x2+1].push_back({y1,y2});
    }
    vi divs;
    for (int i=1;i<n;i++) if (n%i == 0) divs.push_back(i);
    int ans = inf;
    vi p(n+1,0);
    for (int d : divs) {
        p[0] = 0;
        for (int i=1;i<=n;i++) {
            int val = (((i-1)/d)%2 == 0);
            p[i] = p[i-1]+val;
        }
        int sm = p[n];
        int need = 0;
        for (int j = 1;j<=n+1;j++) {
            for (auto it : adds[j]) {
                int old = p[it.ss]-p[it.ff-1];
                sm-=old;
                sm+=(it.ss-it.ff+1)-old;
            }
            for (auto it : rems[j]) {
                sm-=(it.ss-it.ff+1)-(p[it.ss]-p[it.ff-1]);
                sm+=p[it.ss]-p[it.ff-1];
            }
            if (j > n) break;
            if (((j-1)/d)%2 == 0) need+=sm;
            else need+=n-sm;
        }
        ans = min(ans,need);
        ans = min(ans,n*n-need);
    }
    cout << ans << endl;
}  
 
                
                            
signed main() { 
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    #ifdef Dodi
        freopen("in.txt","r",stdin);
        freopen("out.txt","w",stdout);
    #endif
    int t = 1;
    //cin >> t; 
    while (t --> 0) solve();
}

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