Submission #939735

#	Time	Username	Problem	Language	Result	Execution time	Memory
939735		TrinhKhanhDung	Feast (NOI19_feast)	C++14	100 / 100	341 ms	23444 KiB

feast

#include <bits/stdc++.h>

using namespace std;

const int MAX = 3e5 + 10;
const long long oo = (long long)300000 * 1000000000;
const long double EPS = 1e-3;

int N, K;
int a[MAX];
pair<long double, int> dp[MAX][2];

bool OK(long double lambda) {
    dp[0][0] = {0, 0}, dp[0][1] = {-oo, 0};
    for (int i = 1; i <= N; ++i) {
        dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
        dp[i][1] =
            max(make_pair(dp[i - 1][1].first + a[i], dp[i - 1][1].second),
                make_pair(dp[i - 1][0].first + a[i] - lambda,
                          dp[i - 1][0].second + 1));
    }
    return max(dp[N][0], dp[N][1]).second >= K;
};

int main(){
    ios_base::sync_with_stdio(0);

    cin >> N >> K;
    for(int i=1; i<=N; i++){
        cin >> a[i];
    }

    long double lower = 0, upper = oo;
    while (lower + EPS < upper) {
        long double mid = (lower + upper) / 2;
        if (OK(mid)) {
            lower = mid;
        } else {
            upper = mid;
        }
    }
    long double lambda = lower;
    OK(lambda);

    cout << (long long)round(lambda * K + max(dp[N][0], dp[N][1]).first);

    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