Submission #1351608

#	Time	Username	Problem	Language	Result	Execution time	Memory
1351608		PakinDioxide	Feast (NOI19_feast)	C++17	100 / 100	118 ms	2760 KiB

feast

#include <bits/stdc++.h>
#define ll long long

using namespace std;

const int mxN = 3e5+5;

ll a[mxN];

int main() {
    int n, k; cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> a[i];
    auto calc = [&] (ll l) {
        pair <ll, ll> dp[2];
        dp[0] = make_pair(0, 0);
        dp[1] = make_pair(a[1] - l, 1);
        for (int i = 2; i <= n; i++) {
            pair <ll, ll> x, y;
            x = max(dp[0], dp[1]);
            y = max(
                    make_pair(dp[0].first + a[i] - l, dp[0].second + 1),
                    make_pair(dp[1].first + a[i], dp[1].second)
                   );
            dp[0] = x, dp[1] = y;
        }
        return max(dp[0], dp[1]);
    };
    ll L = 0, R = 3e14, ans = 0;
    while (L <= R) {
        ll x = L + (R-L)/2;
        if (calc(x).second >= k) L = x+1, ans = x;
        else R = x-1;
    }
    cout << calc(ans).first + k * ans << '\n';
}

• 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