Submission #1192097

#	Time	Username	Problem	Language	Result	Execution time	Memory
1192097		Aiperiii	Fancy Fence (CEOI20_fancyfence)	C++20	43 / 100	15 ms	1864 KiB

fancyfence

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
#define pb push_back
const int mod=1e9+7;
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n;
    cin>>n;
    
    bool sb2=1;
    vector <int> h(n),w(n);
    for(int i=0;i<n;i++){
        cin>>h[i];
        if(h[i]>2)sb2=0;
    }
    
    for(int i=0;i<n;i++){
        cin>>w[i];
    }
    int x=0,sum=0;
    for(int i=0;i<n;i++){
        x+=w[i];
        sum+=w[i];
    }
    int y=x+1;
    int ans=0;
    if(sb2){
        if(x%2==0)x/=2;
        else y/=2;
        ans+=((x%mod)*(y%mod))%mod;
        ans%=mod;
        
        x=0;
        for(int i=0;i<n;i++){
            if(h[i]==2){
                x+=w[i];
            }
            else{
                y=x+1;
                ans+=((x%mod)*(y%mod))%mod;
                ans%=mod;
                x=0;
                
            }
        }
        if(x!=0){
            y=x+1;
            ans+=((x%mod)*(y%mod))%mod;
            ans%=mod;
        }
        cout<<ans%mod<<"\n";
        return 0;
    }
    
    bool sm=1;
    for(int i=0;i<n;i++){
        if(h[i]!=h[0])sm=0;
    }
    
    if(sm){
        if(x%2==0)x/=2;
        else y/=2;
        
        int z=((x%mod)*(y%mod))%mod;
        
        int a=h[0];
        int b=h[0]+1;
        if(a%2==0)a/=2;
        else b/=2;
        
        int c=((a%mod)*(b%mod))%mod;
        
        ans=(z*c)%mod;
        cout<<ans<<"\n";
        return 0;
    }
    
    
    for(int i=0;i<n;i++){
        
        int a=h[i];
        int b=h[i]+1;
        if(a%2==0)a/=2;
        else b/=2;
        int c=((a%mod)*(b%mod))%mod;
        
        x=sum;
        y=x+1;
        if(x%2==0)x/=2;
        else y/=2;
        int z=((x%mod)*(y%mod))%mod;
        
        x=sum;
        int q=x-w[i];
        int r=q+1;
        if(q%2==0)q/=2;
        else r/=2;
        int t=((q%mod)*(r%mod))%mod;
        
        
        int d=(z+mod-t)%mod;
        //cout<<d<<"\n";
        d=(d*c)%mod;
        ans+=d;
        ans%=mod;
        
        
        sum-=w[i];
        
    }
    cout<<ans<<"\n";
}
/*
 10^14*(10^14+1)/2
*/

• Subtask 1: 0 / 0
• Subtask 2: 0 / 12
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 0 / 18
• Subtask 7: 0 / 27