Submission #939720

#	Time	Username	Problem	Language	Result	Execution time	Memory
939720		TrinhKhanhDung	Feast (NOI19_feast)	C++14	4 / 100	206 ms	23168 KiB

feast

#include <bits/stdc++.h>

using namespace std;

const int MAX = 3e5 + 10;
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] = make_pair(0.0, 0);
    dp[0][1] = make_pair(-1.18, 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].second, 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 lo = 0, hi = (long double)1e14;
    while(lo + EPS < hi){
        long double mid = (lo + hi) / 2;

        if(OK(mid)){
            lo = mid;
        }
        else{
            hi = mid;
        }
    }

    OK(lo);

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

    return 0;
}

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