Submission #251766

#	Time	Username	Problem	Language	Result	Execution time	Memory
251766		tutis	Hacker (BOI15_hac)	C++17	20 / 100	64 ms	14316 KiB

hac

/*input
4
7 6 8 4
*/
#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename K>
using ordered_map = tree<T, K, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	int n;
	cin >> n;
	ll h[n];
	for (int i = 0; i < n; i++)
		cin >> h[i];
	ll k = (n + 1) / 2;
	int sz = n + k;
	ll s[sz + 1];
	s[0] = 0;
	for (int i = 1; i <= sz; i++)
		s[i] = s[i - 1] + h[i % n];
	vector<ll>X;
	for (int i = k; i <= sz; i++)
		X.push_back(s[i] - s[i - k]);
	deque<pair<ll, ll>>A;
	for (int i = 0; i < k; i++)
	{
		while (!A.empty() && A.back().first >= X[i])
			A.pop_back();
		A.push_back({X[i], i});
	}
	ll ans = A[0].first;
	for (int i = k; i < (int)X.size(); i++)
	{
		while (!A.empty() && A.back().first >= X[i])
			A.pop_back();
		A.push_back({X[i], i});
		while (A[0].second <= i - k)
			A.pop_front();
		ans = max(ans, A[0].first);
	}
	cout << ans << "\n";
	return 0;
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 40