Submission #981175

#	Time	Username	Problem	Language	Result	Execution time	Memory
981175		beaboss	Feast (NOI19_feast)	C++14	100 / 100	141 ms	15232 KiB

feast

// Source: https://oj.uz/problem/view/NOI19_feast
// 

#include "bits/stdc++.h"

using namespace std;
#define FOR(i, a, b) for (ll i = a; i < b; i++)
typedef long long ll;

typedef pair<ll, ll> pii;
#define s second
#define f first

const ll N = 3e5 + 10;
ll a[N];
pii dp[N][2];
ll n, k;

pii solve(ll l) {
	dp[0][0] = {0, 0};
	dp[0][1] = {a[0] - l, 1};

	FOR(i, 1, n) {
		dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
		dp[i][1] = max(make_pair(dp[i-1][0].f + a[i] - l, dp[i-1][0].s + 1), make_pair(dp[i-1][1].f + a[i], dp[i-1][1].s));
	}
	return max(dp[n-1][1], dp[n-1][0]);

}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	cin >> n >> k;

	FOR(i, 0 ,n) cin >> a[i];

	ll lo = 0;
	ll hi = 1e18;

	while (lo < hi) {
		ll m = (lo + hi + 1)/2;
		pii res = solve(m);
		if (res.s >= k) lo = m;
		else hi = m -1;
	}
	// cout << lo << solve(lo).f << endl;
	cout << solve(lo).f + k * lo << endl;

}

• 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