Submission #704749

#	Time	Username	Problem	Language	Result	Execution time	Memory
704749		Markomafko972	Fancy Fence (CEOI20_fancyfence)	C++14	100 / 100	51 ms	3808 KiB

fancyfence

#include <bits/stdc++.h>
#define X first
#define Y second
#define pb push_back
#define pii pair<int, int>
typedef long long ll;
using namespace std;

const int MOD = 1e9 + 7;
const ll INF = 1e18;
const int OFF = (1 << 20);

int n;
pii p[100005];
stack<pii> s;

int add(int x, int y) {
	if (x+y < MOD) return x+y;
	return x+y-MOD;
}

int mul(int x, int y) {
	return (ll)x * (ll)y % MOD;
}

int pot(int x, int y) {
	if (y == 0) return 1;
	if (y == 1) return x;
	int out = pot(x, y/2);
	out = mul(out, out);
	if (y % 2 == 1) out = mul(out, x);
	return out;
}

int main () {

	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	cin >> n;
	for (int i = 0; i < n; i++) cin >> p[i].X;
	for (int i = 0; i < n; i++) cin >> p[i].Y;
	
	int sol = 0;
	for (int i = 0; i <= n; i++) {
		int kol = 0;
		while (s.size() > 0 && s.top().X >= p[i].X) {
			ll h = add(p[i].X, 1);
			h = add(h, s.top().X);
			h = mul(h, s.top().X-p[i].X);
			h = mul(h, pot(2, MOD-2));
			//cout << h << " ";
			
			ll tren = add(kol, kol);
			tren = add(tren, s.top().Y);
			tren = add(tren, 1);
			tren = mul(tren, s.top().Y);
			tren = mul(tren, pot(2, MOD-2));
			//cout << tren << " ";
			tren = mul(tren, h);
			sol = add(sol, tren);
			//cout << s.top().X << " " << sol << endl;
			
			kol = add(kol, s.top().Y);
			s.pop();
		}
		kol = add(kol, p[i].Y);
		s.push({p[i].X, kol});
	}
	cout << sol;

	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