Submission #1070833

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070833		TAhmed33	Feast (NOI19_feast)	C++98	100 / 100	154 ms	15236 KiB

feast

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 3e5 + 25;
ll a[MAXN], n, k;
pair <ll, ll> eval (ll mid) {
	pair <ll, ll> dp[n + 1][2];
	dp[1][0] = {0, 0};
	dp[1][1] = {a[1] - mid, 1};
	for (int i = 2; i <= n; i++) {
		dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
		pair <ll, ll> g = {dp[i - 1][0].first + a[i] - mid, dp[i - 1][0].second + 1};
		pair <ll, ll> h = {dp[i - 1][1].first + a[i], dp[i - 1][1].second};
		dp[i][1] = max(g, h);
		dp[i][0] = max(dp[i][0], {0ll, 0ll});
		dp[i][1] = max(dp[i][1], {a[i] - mid, 1ll});
	}
	return max({dp[n][0], dp[n][1], {0ll, 0ll}});
}
void solve () {
	cin >> n >> k;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	ll l = 0, r = 1e18, ans = 0;
	while (l <= r) {
		ll mid = (l + r) / 2;	
		if (eval(mid).second >= k) {
			l = mid + 1; ans = mid; 
		} else {
			r = mid - 1;
		}
	}
	cout << eval(ans).first + ans * k << '\n';
}		
signed main () {
	ios::sync_with_stdio(0); cin.tie(0);
	int tc = 1; //cin >> tc;
	while (tc--) solve();
}

• 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