Submission #647350

#	Time	Username	Problem	Language	Result	Execution time	Memory
647350		myrcella	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	31 ms	3764 KiB

fancyfence

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

#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}

int n;
const int maxn  = 1e5+10;

int h[maxn],w[maxn];
stack <pii> q;

int main() {
//	freopen("input.txt","r",stdin);	
	std::ios::sync_with_stdio(false);cin.tie(0);
	cin>>n;
	rep(i,0,n) cin>>h[i];
	rep(i,0,n) cin>>w[i];
	int ans = 0,sum = 0;
	rep(i,0,n) {
		int curw = w[i];
		while (!q.empty() and q.top().fi>=h[i]) {
			inc(curw,q.top().se);
			dec(sum,1ll*q.top().fi*(q.top().fi+1)/2%mod*q.top().se%mod);
	//		debug(sum);
			q.pop();
		}
		q.push({h[i],curw});
		inc(sum,1ll*h[i]*(h[i]+1)/2%mod*curw%mod);
	//	debug(sum);
		inc(ans,1ll*sum*w[i]%mod);
		dec(ans,(1ll*w[i]*(w[i]-1)/2%mod)*(1ll*h[i]*(h[i]+1)/2%mod)%mod);
	//	debug(ans);
	}
	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