Submission #1210002

#	Time	Username	Problem	Language	Result	Execution time	Memory
1210002		nmdminh	Feast (NOI19_feast)	C++20	100 / 100	57 ms	7396 KiB

feast

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

ll a[300005];
pair<ll, ll> dp[300005];

void calc(int n, ll c) {
    pair<ll, ll> mx(0, 0);
    for (int i = 1; i <= n; ++i) {
        dp[i] = max(dp[i - 1], {mx.first + a[i] - c, mx.second - 1});
        mx = max(mx, {dp[i].first - a[i], dp[i].second});
    }
}

void solve() {
    int n, k;
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        a[i] += a[i - 1];
    }

    ll l = 0, r = 1e15;
    while (l < r) {
        ll mid = (l + r) / 2;
        calc(n, mid);
        if (-dp[n].second <= k) r = mid;
        else l = mid + 1;
    }

    calc(n, l);
    cout << dp[n].first + l * k << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    solve();
    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