Submission #685333

#	Time	Username	Problem	Language	Result	Execution time	Memory
685333		dostigator	Chessboard (IZhO18_chessboard)	C++17	70 / 100	229 ms	4256 KiB

chessboard

#include <bits/stdc++.h>

using namespace std;

#define all(a) a.begin(),a.end()
#define pb push_back
#define vt vector
#define endl '\n'
#define Y second
#define X first
typedef long long ll;
typedef long double ld;
const ll mod=1e9+7;
const ll INF=1e18;
const int inf=1e9;
const int N=2e5+505;
const int M=3e3+10;
const int dx[]={0,0,1,-1};
const int dy[]={1,-1,0,0};

/*From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH*/

ll n,k;
pair<ll,ll>vls[N];

void solve(){
	cin>>n>>k;
	for(int i=1; i<=k; ++i){
		int x1,y1,x2,y2;
		cin>>x1>>y1>>x2>>y2;
		vls[i]={x1,y1};
	}vt<ll>lst;
	for(ll d=1; d*d<=n; ++d){
		if(n%d==0){
			lst.pb(d);
			if(n/d!=d)lst.pb(n/d);
		}
	}ll ans=INF;
	for(ll del:lst){
		ll heh=n/del;
		heh*=heh;
		ll cnt=heh-(heh/2),cnt2=heh/2;
		cnt*=del*del;
		cnt2*=del*del;
		//cout<<del<<' '<<cnt<<' '<<cnt2<<endl;
		for(int i=1; i<=k; ++i){
			ll x,y;
			x=vls[i].X;
			y=vls[i].Y;
			x=(x+(del-1))/del;
			y=(y+(del-1))/del;
			if(((x+y)%2)==0) {
				cnt--;
				cnt2++;
			}else{
				cnt++;
				cnt2--;
			}
		}if(del==n){
			ans=min(ans,cnt);
			continue;
		}
		ans=min({ans,cnt,cnt2});
		//cout<<del<<' '<<cnt<<' '<<cnt2<<endl;
	}cout<<ans<<endl;
}

int main(){
	//srand(time(0));
	//freopen("hotel.in","r",stdin);
	//freopen("hotel.out","w",stdout);
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int tt=1,lolol=0;
//	cin>>tt;
	while(tt--) {
		//cout<<"Case "<<++lolol<<": ";
		solve();
	}
}

Compilation message (stderr)

chessboard.cpp: In function 'int main()':
chessboard.cpp:79:11: warning: unused variable 'lolol' [-Wunused-variable]
   79 |  int tt=1,lolol=0;
      |           ^~~~~

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