Submission #539032

#	Time	Username	Problem	Language	Result	Execution time	Memory
539032		_karan_gandhi	Feast (NOI19_feast)	C++17	51 / 100	1063 ms	25940 KiB

feast

#include <bits/stdc++.h>
using namespace std;

#define all(v) v.begin(), v.end()
#define endl '\n'
#define pl(var) " [" << #var << ": " << (var) << "] "
#define ll long long

void solve() {
	// dp[i][j] = the max sum that can be obtained if j subsegments are chosen and last subsegment ends at i

	// dp[i][j] = dp[0..i][j-1]
	int n, k; cin >> n >> k;
	vector<ll int> arr(n); for (int i = 0; i < n; i++) {
		cin >> arr[i];
	}

	bool good = 1;
	bool one = 0;
	for (int i = 0; i < n; i++) {
		if (arr[i] < 0 && !one) {
			good = 0;
			one = 1;
		} else if (arr[i] < 0 && one) {
			one = 0;
			break;
		}
	}

	if (good) {
		ll int cur = 0;
		for (int i = 0; i < n; i++) {
			cur += arr[i];
		}

		cout << cur << endl;
		return;
	}

	if (one) {
		// depends on the value of k;
		ll int start = 0;
		ll int end = 0;
		ll int all = 0;
		bool instart = 1;

		for (int i = 0; i < n; i++) {
			all += arr[i];
			if (arr[i] < 0) {
				instart = 0;
				continue;
			}

			if (instart) {
				start += arr[i];
			} else {
				end += arr[i];
			}
		}

		if (k == 1) {
			cout << max({start, end, all}) << endl;
		} else {
			cout << start + end << endl;
		}

		return;
	}

	vector<vector<ll int>> dp(n + 1, vector<ll int>(k + 1, 0));

	ll int ans = 0;
	ll int mn = 0;
	ll int pref = 0;
	for (int i = 0; i < n; i++) {
		pref += arr[i];
		mn = min(pref, mn);
		dp[i][1] = max(pref - mn, pref);
		ans = max(ans, dp[i][1]);
		if (arr[i] < 0) good = 0;
	}

	for (int i = 2; i <= k; i++) {
		for (int j = i - 1; j < n; j++) {
			ll int cur = arr[j]; 
			ll int best = arr[j];
			for (int k = j - 1; k >= 0; k--) {
				dp[j][i] = max(dp[k][i - 1] + best, dp[j][i]);
				cur += arr[k];
				best = max(best, cur);
			}
			ans = max(ans, dp[j][i]);
		}
	}

	cout << ans << endl;
}

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

	int T = 1;
	// cin >> T;
	while (T--)
		solve();
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29