Submission #1069119

#	Time	Username	Problem	Language	Result	Execution time	Memory
1069119		Andrey	Fancy Fence (CEOI20_fancyfence)	C++14	100 / 100	62 ms	10440 KiB

fancyfence

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

const long long MOD = 1e9+7;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    long long n,ans = 0;
    cin >> n;
    vector<long long> haha(n+1);
    vector<long long> bruh(n+1);
    for(long long i = 1; i <= n; i++) {
        cin >> haha[i];
    }
    for(long long i = 1; i <= n; i++) {
        cin >> bruh[i];
        bruh[i]+=bruh[i-1];
    }
    vector<pair<long long,long long>> wut(0);
    for(long long i = 1; i <= n; i++) {
        wut.push_back({haha[i],i});
    }
    sort(wut.begin(),wut.end());
    set<long long> idk;
    idk.insert(0);
    idk.insert(n+1);
    for(long long i = 0; i < n; i++) {
        long long p = wut[i].second,h = wut[i].first;
        long long r = *idk.lower_bound(p);
        long long l = *(--idk.upper_bound(p));
        idk.insert(p);
        long long x = (bruh[r-1]-bruh[l])%MOD,y = (bruh[r-1]-bruh[p])%MOD,z = (bruh[p-1]-bruh[l])%MOD;
        ans+=((x*(x+1)/2-y*(y+1)/2-z*(z+1)/2+MOD*MOD*2)%MOD)*((h*(h+1)/2)%MOD);
        ans%=MOD;
    }
    cout << ans;
    return 0;
}

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