Submission #959379

#	Time	Username	Problem	Language	Result	Execution time	Memory
959379		ALTAKEXE	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	23 ms	4212 KiB

fancyfence

#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define ll long long
const ll mod=1e9+7;
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin>>n;
	vector<ll> h(n+1,0), w(n+1,0);
	for(int i=0;i<n;++i) cin>>h[i];
	for(int i=0;i<n;++i) cin>>w[i];
	n++;
	vector<pair<ll,ll>> t; 
	t.push_back({0,0});
	ll ans=0;
	for(int i=0;i<n;++i) {
		ll sum=0;
		while(t.back().f>h[i]) { 
			ll mn=max(h[i],t[t.size()-2].f); 
			ll mx=t.back().f-mn; 
			sum=(sum+t.back().s)%mod;
			t.pop_back();
			ans+=(mx*(mx+1)%mod*500000004%mod+mx*mn%mod)*(sum*(sum+1)%mod*500000004%mod)%mod;
			ans%=mod;
		}
		if(t.back().f==h[i]) t.back().s=(t.back().s+sum+w[i])%mod;
		else t.push_back({h[i], (sum+w[i])%mod});
	}
	cout<<ans<<endl;
	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