Submission #557530

#	Time	Username	Problem	Language	Result	Execution time	Memory
557530		Alexandruabcde	Feast (NOI19_feast)	C++14	100 / 100	736 ms	26912 KiB

feast

#include <bits/stdc++.h>

using namespace std;

typedef long double LD;
typedef long long LL;
typedef pair <LD, int> PLDI;
constexpr int NMAX = 3e5 + 5;
constexpr LD INF = 1LL * 1e14;

int N, K;

LD A[NMAX];
PLDI dp[NMAX][2];

PLDI Check (LD penalty) {
    dp[1][0] = {0, 0};
    dp[1][1] = {A[1] - penalty, 1};

    for (int i = 2; i <= N; ++ i ) {
        dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
        dp[i][1] = max(make_pair(dp[i-1][0].first + A[i] - penalty, dp[i-1][0].second + 1),
                       make_pair(dp[i-1][1].first + A[i], dp[i-1][1].second));
    }

    return max(dp[N][0], dp[N][1]);
}

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

    cin >> N >> K;

    for (int i = 1; i <= N; ++ i )
        cin >> A[i];

    int cnt_op = 100;
    LD st = 0, dr = INF;
    while (st <= dr && cnt_op) {
        LD mij = .5 * (st + dr);
        -- cnt_op;

        PLDI pos_ans = Check(mij);
        if (pos_ans.second >= K)
            st = mij;
        else dr = mij;
    }

    PLDI ans = Check(dr);
    LL val = round(ans.first + (LD)K * dr);

    cout << val << '\n';

    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