Submission #898417

#	Time	Username	Problem	Language	Result	Execution time	Memory
898417		LCJLY	Fancy Fence (CEOI20_fancyfence)	C++14	30 / 100	27 ms	4184 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << "  " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << "  " << j << " " << #i << "  " << q << " " << #p << endl; 
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;

int mod=1e9+7;
int f(int a, int b){
	a%=mod;
	b%=mod;
	return (a*b)%mod;
}

int calc(int n){
	int hold=f(f(n,n+1),500000004);
	return hold;
}

int len(int a, int b){
	return b-a;
}

void solve(){	
	int n;
	cin >> n;

	pii arr[n];
	for(int x=0;x<n;x++){
		cin >> arr[x].first;
	}
	
	for(int x=0;x<n;x++){
		cin >> arr[x].second;
		//w+=arr[x].second;
	}
	
	//int last=0;
	//int counter=0;
	//int pos=1;
	//for(int x=0;x<n;x++){
		//if(arr[x].first>last){
			//int hold=(calc(arr[x].first)-calc(last)+mod)%mod;
			//counter=(counter+f(hold,calc(len(pos,w))))%mod;
			//last=arr[x].first;
		//}
		//pos+=arr[x].second;
	//}
	
	//counter%=mod;
	
	//cout << counter;
	
	vector<pii>stk; //h pos
	stk.push_back({0,0});
	int pos=1;
	
	int counter=0;
	for(int x=0;x<n;x++){
		while(!stk.empty()&&arr[x].first<stk.back().first){
			int sz=stk.size();
			int w=len(stk[sz-1].second,pos);
			int h1=stk[sz-1].first;
			int h2=stk[sz-2].first;
			int hold=(calc(h1)-calc(h2)+mod)%mod;
			counter=(counter+f(hold,calc(w)))%mod;
			stk.pop_back();
		}
		if(arr[x].first!=stk.back().first){
			stk.push_back({arr[x].first,pos});
		}
		pos+=arr[x].second;
	}
	
	while(stk.size()>1){
		int sz=stk.size();
		int w=len(stk[sz-1].second,pos);
		int h1=stk[sz-1].first;
		int h2=stk[sz-2].first;
		int hold=(calc(h1)-calc(h2)+mod)%mod;
		counter=(counter+f(hold,calc(w)))%mod;
		stk.pop_back();
	}
	
	cout << counter;
}
 
int32_t main(){										
	ios::sync_with_stdio(0);	
	cin.tie(0);
	//freopen("redistricting.in", "r", stdin);
	//freopen("redistricting.out", "w", stdout);
	int t=1;
	//cin >> t;
	while(t--){
		solve();
	}	
}

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