Submission #500352

#	Time	Username	Problem	Language	Result	Execution time	Memory
500352		dostigator	Chessboard (IZhO18_chessboard)	C++14	39 / 100	188 ms	11888 KiB

chessboard

// author lox:(
#pragma GCC optimize("O3")
#pragma GCC target("popcnt")
#include <bits/stdc++.h>
using namespace std;
#define IZhO_SILVER ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define popcnt __builtin_popcount
#define all(a) a.begin(),a.end()
#define low_b lower_bound
#define up_b upper_bound
#define vii vector<pair<ll,ll>>
#define vll vector<pair<ll,ll>>
#define pii pair<ll,ll>
#define mii map<ll,ll>
#define pll pair<ll,ll>
#define mll map<ll,ll>
#define vi vector<ll>
#define vl vector<ll>
#define pb push_back
#define endl '\n'
#define Y second
#define X first
typedef long double ld;
typedef long long ll;
const long long dx[4]={1,-1,0,0},dy[4]={0,0,1,-1},col=107,N=1e6+777;
const ll mod=1e9+7,inf=1e18;
void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
ll binpow(ll n,ll k){if(k<0)return 0ll;if(k==0)return 1ll;if(k%2)return (binpow(n,k-1)*n)%mod;ll kk=binpow(n,k/2)%mod;return (kk*kk)%mod;}
ll a[2001][2001];
ll n,k;
void solve(){
    cin>>n>>k;
    if(k==0){
        ll x=n*n/2;
        for(ll i=n/2; i>=1; --i)if(n%i==0)x=min(x,i*i*((n/i)*(n/i)/2));
        cout<<x;
        return;
    }
    if(n<=1000){
        for(ll i=1; i<=k; ++i){
            ll x,y,tox,toy;
            cin>>x>>y>>tox>>toy;
            a[x][y]=1;
        }
        ll ans=mod-10;
        for(ll d=1; d*d<=n; ++d){
            if(n%d!=0) continue;
            ll res=0,res2=0;
            for(ll i=1; i<=n; ++i){
                for(ll j=1; j<=n; ++j){
                    ll x=(i+(d-1))/d;
                    ll y=(j+(d-1))/d;
                    if((x+y)%2 && a[i][j]) ++res2;
                    if((x+y)%2 && !a[i][j]) ++res;
                    if(!((x+y)%2) && a[i][j]) ++res;
                    if(!((x+y)%2) && !a[i][j]) ++res2;
                }
            }
            ans=min({ans,res,res2});
            //cout<<d<<' '<<res<<' '<<res2<<endl;
            ll f=n/d;
            res=0,res2=0;
            for(ll i=1; i<=n; ++i){
                for(ll j=1; j<=n; ++j){
                    ll x=(i+(f-1))/f;
                    ll y=(j+(f-1))/f;
                    if((x+y)%2 && a[i][j]) ++res2;
                    if((x+y)%2 && !a[i][j]) ++res;
                    if(!((x+y)%2) && a[i][j]) ++res;
                    if(!((x+y)%2) && !a[i][j]) ++res2;
                }
            }
            if(d==1){
                ans=min(ans,max(res,res2));
                continue;
            }
            ans=min({ans,res,res2});
            //cout<<d<<' '<<res<<' '<<res2<<endl;
        }
        cout<<ans<<endl;
        return;
    }
    ll x=n*n/2;
    ll x2=x+1;
    for(ll c=0, i1,i2,j1,j2;c<k; ++c){
        cin>>i1>>j1>>i2>>j2;
        for(ll i=i1; i<=i2; ++i)
            for(ll j=j1; j<=j2; ++j)
            {
                if(i%2==j%2) x++,x2--;
                if(i%2!=j%2) x2++,x--;
            }
        cout<<min(x,x2);
    }
}
/*
6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6*/
int main() {
    //fre_open();
    IZhO_SILVER;
    ll tt=1;
    //cin>>tt;
    while(tt--) solve();
}

Compilation message (stderr)

chessboard.cpp: In function 'void fre_open()':
chessboard.cpp:27:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 | void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
chessboard.cpp:27:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 | void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
      |                                              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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