Submission #906418

#	Time	Username	Problem	Language	Result	Execution time	Memory
906418		Ludissey	Fancy Fence (CEOI20_fancyfence)	C++14	15 / 100	26 ms	3932 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
#define int long long
 
int n,m;
int mod=1e9+7;
int clc(int x) { return (((x*(x+1)))/(long long)2)%mod; }
signed main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    cin >> n;
    vector<int> h(n);
    vector<int> w(n);
    int totalw=0;
    for (int i = 0; i < n; i++) cin>>h[i];
    for (int i = 0; i < n; i++) { cin >> w[i]; totalw+=w[i]; }
    int outp=0;
    for (int i = 0; i < n; i++)
    {
        int lasth=0;
        if(i>0) lasth=h[i-1];
        outp+=(clc(totalw%mod)*clc(h[i]%mod))%mod-(clc(totalw%mod)*clc(lasth%mod))%mod;
        outp%=mod;
        totalw-=w[i];
    }
    outp%=mod;
    cout << outp << "\n";
    return 0;
}

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