Submission #558052

#	Time	Username	Problem	Language	Result	Execution time	Memory
558052		Tenis0206	Fancy Fence (CEOI20_fancyfence)	C++11	0 / 100	1 ms	340 KiB

fancyfence

#include <bits/stdc++.h>
#define int long long

using namespace std;

const int Mod = 1e9 + 7;

int n;

int h[100005],w[100005];
int sp[100005];

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>h[i];
    }
    for(int i=1;i<=n;i++)
    {
        cin>>w[i];
        sp[i] = (sp[i-1] + w[i]) % Mod;
    }
    stack<int> st,st_sum;
    st.push(0);
    long long sum = 0, rez = 0;
    for(int i=1;i<=n;i++)
    {
        while(h[i]<=h[st.top()])
        {
            sum = (sum - st_sum.top() + Mod) % Mod;
            st_sum.pop();
            st.pop();
        }
        rez += 1LL * sum * w[i] % Mod;
        rez %= Mod;
        rez += w[i] * (w[i] + 1) / 2 % Mod * (h[i] * (h[i]+1) / 2 % Mod) % Mod;

        int c_sum = (sp[i] - sp[st.top()] + Mod) % Mod * (h[i] * (h[i] + 1) / 2 % Mod) % Mod;
        sum += c_sum;
        sum %= Mod;
        st_sum.push(c_sum);
        st.push(i);
    }
    cout<<rez<<'\n';
    return 0;
}

• 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