Submission #984853

#	Time	Username	Problem	Language	Result	Execution time	Memory
984853		IBory	Feast (NOI19_feast)	C++17	100 / 100	141 ms	15440 KiB

feast

#include <bits/stdc++.h>
#define pii pair<ll, ll>
typedef long long ll;
using namespace std;

const int MAX = 300003;
ll A[MAX];
pii dp[MAX][2];

const pii operator+(const pii a, const pii b) {
	return {a.first + b.first, a.second + b.second};
}

pii Check(ll N, pii p) {
	dp[0][0] = {0, 0};
	dp[0][1] = {-1e18, 0};
	for (int i = 1; i <= N; ++i) {
		dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
		dp[i][1] = max(dp[i - 1][1] + pii{A[i], 0}, dp[i - 1][0] + pii{A[i], 1} + p);
	}
	return max(dp[N][0], dp[N][1]);
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	ll N, K;
	cin >> N >> K;
	for (int i = 1; i <= N; ++i) cin >> A[i];

	ll l = 0, r = 1e15;
	while (l + 1 < r) {
		ll mid = (l + r) >> 1;
		pii p = Check(N, pii{-mid, 0});
		(p.second < K ? r : l) = mid;
	}

	pii t = Check(N, pii{-l, 0});
	ll ans = t.first + t.second * l;
	cout << ans;
	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29