Submission #898374

#	Time	Username	Problem	Language	Result	Execution time	Memory
898374		LCJLY	Fancy Fence (CEOI20_fancyfence)	C++14	13 / 100	24 ms	3164 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+1;
}

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;
	}
	
	int last=-1;
	int counter=0;
	int pos=1;
	for(int x=0;x<n;x++){
		if(arr[x].first==1){
			counter=(counter+calc(len(1,pos+arr[x].second-1))-calc(len(1,pos-1))+mod)%mod;
			last=-1;
		}
		else if(arr[x].first==2){
			if(last==-1) last=pos;
			int hold=calc(len(last,pos+arr[x].second-1))-calc(len(last,pos-1));
			hold=(hold+mod)%mod;
			counter=(counter+2*hold)%mod;
			counter=(counter+calc(len(1,pos+arr[x].second-1))-calc(len(1,pos-1))+mod)%mod;
		}
		//show(counter,counter);
		pos+=arr[x].second;
	}
	
	
	
	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: 13 / 13
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 18
• Subtask 7: 0 / 27