Submission #926360

#	Time	Username	Problem	Language	Result	Execution time	Memory
926360		Nonoze	Hacker (BOI15_hac)	C++17	100 / 100	42 ms	5460 KiB

hac

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize(2)

int n, k, m;
vector<int> a;

void solve() {
	cin >> n;
	a.clear(), a.resize(n);
	int mid=n/2+n%2;
	int sm=0;
	for (int i=0; i<mid; i++) {
		cin >> a[i];
		sm+=a[i];
	}
	for (int i=mid; i<n; i++) cin >> a[i];
	vector<int> sum(1, sm);
	deque<int> curr;
	curr.push_back(0);
	for (int i=1; i<mid; i++) {
		sum.push_back(sum.back()+a[(i+mid-1)%n]-a[i-1]);
		while (!curr.empty() && sum[curr.front()]>=sum[i]) curr.pop_front();
		curr.push_front(i);
	}
	for (int i=mid; i<n; i++) sum.push_back(sum.back()+a[(i+mid-1)%n]-a[i-1]);
	int ans=0;
	for (int i=mid; i<n+mid; i++) {
		ans=max(ans, sum[curr.back()]);
		while (!curr.empty() && sum[curr.front()]>=sum[i%n]) curr.pop_front();
		if (!curr.empty() && curr.back()==i-mid) curr.pop_back();
		curr.push_front(i%n);
	}
	cout << ans << endl;
	return;
}

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	solve();
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40