Submission #1234980

#	Time	Username	Problem	Language	Result	Execution time	Memory
1234980		jundi	Fancy Fence (CEOI20_fancyfence)	C++20	0 / 100	1 ms	328 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;

#define lint long long int
int mod=1e9+7;

int main(){
    int n;
    cin>>n;
    vector<lint> h(n);
    vector<lint> w(n);
    vector<lint> cntw(n,0);
    for(int i=0;i<n;i++){
        cin>>h[i];
    }
    for(int i=0;i<n;i++){
        cin>>w[i];
    }
    cntw[n-1]=w[n-1];
    for(int i=n-2;i>=0;i--){
        cntw[i]=cntw[i+1]+w[i];
        cntw[i]%=mod;
    }
    for(int i=1;i<n;i++){
        if(w[i]==w[i-1]) cntw[i]==cntw[i-1];
    }
    // lint sum=(((1+cntw[n-1])%mod)*(cntw[n-1]%mod)/2);
    // sum%=mod;
    lint reh=0;
    lint sum=0;
    for(int i=0;i<n;i++){
        if(i>0) if(h[i]!=h[i-1]) reh=h[i-1];
        if(h[i]!=h[i+1] || i==n-1){
            lint huh=(((cntw[i]+1)%mod)*(cntw[i]%mod)/2);
            huh%=mod;
            lint huh2=(((h[i]+1)%mod)*(h[i]%mod)/2);
            huh2%=mod;
            huh2-=reh;
            sum+=huh*huh2; sum%=mod;
            // cout<<sum<<endl;
            reh=0;
        }
        
    }
    cout<<sum;
}

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