Submission #101130

#	Time	Username	Problem	Language	Result	Execution time	Memory
101130		luciocf	Hacker (BOI15_hac)	C++14	100 / 100	706 ms	22508 KiB

hac

#include <bits/stdc++.h>

using namespace std;

const int maxn = 5e5+10;
const int inf = 1e9+10;

int n;
int v[2*maxn], soma[maxn];
int tree[4*maxn], lazy[4*maxn];

void init(void)
{
	for (int i = 0; i < 4*maxn; i++)
		tree[i] = lazy[i] = inf;
}

void flush(int node, int l, int r)
{
	if (lazy[node] == inf) return;

	tree[node] = min(tree[node], lazy[node]);

	if (l != r)
	{
		lazy[2*node] = min(lazy[2*node], lazy[node]);
		lazy[2*node+1] = min(lazy[2*node+1], lazy[node]);
	}

	lazy[node] = inf;
}

void upd(int node, int l, int r, int a, int b, int v)
{
	flush(node, l, r);
	if (l > b || r < a) return;

	if (l >= a && r <= b)
	{
		lazy[node] = v;
		flush(node, l, r);
		return;
	}

	int mid = (l+r)>>1;

	upd(2*node, l, mid, a, b, v); upd(2*node+1, mid+1, r, a, b, v);

	tree[node] = min(tree[2*node], tree[2*node+1]);
}

int query(int node, int l, int r, int a, int b)
{
	flush(node, l, r);
	if (l > b || r < a) return inf;

	if (l >= a && r <= b) return tree[node];

	int mid = (l+r)>>1;

	return min(query(2*node, l, mid, a, b), query(2*node+1, mid+1, r, a, b));
}

int main(void)
{
	init();

	cin >> n;

	int m = (n+1)/2;

	for (int i = 1; i <= n; i++)
	{
		cin >> v[i];
		v[n+i] = v[i];
	}

	int soma = 0;
	for (int i = 1; i <= m; i++)
		soma += v[i];

	upd(1, 1, n, 1, m, soma);

	int ans = 0;
	for (int i = m + 1; i-m+1 <= n; i++)
	{
		soma -= v[i-m];
		soma += v[i];

		if (i <= n) upd(1, 1, n, i-m+1, i, soma);
		else
		{
			upd(1, 1, n, i-m+1, n, soma); upd(1, 1, n, 1, i-n, soma);
		}
	}

	for (int i = 1; i <= n; i++) 
		ans = max(ans, query(1, 1, n, i, i));

	cout << ans << "\n";
}

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