Submission #1224923

#	Time	Username	Problem	Language	Result	Execution time	Memory
1224923		AlgorithmWarrior	Feast (NOI19_feast)	C++20	100 / 100	177 ms	8632 KiB

feast

#include <bits/stdc++.h>

using namespace std;

struct answer{
    long long sum;
    int cnt;
    bool operator<(answer ot){
        if(sum!=ot.sum)
            return sum<ot.sum;
        return cnt>ot.cnt;
    }
};

int const NMAX=300005;
answer dp[NMAX];
int n,k;
int v[NMAX];
long long sp[NMAX];

void read(){
    cin>>n>>k;
    int i;
    for(i=1;i<=n;++i){
        cin>>v[i];
        sp[i]=sp[i-1]+v[i];
    }
}

answer get_dp(long long lambda){
    answer best={0,0};
    int i;
    for(i=1;i<=n;++i){
        dp[i]={best.sum+sp[i]-lambda,best.cnt+1};
        if(dp[i]<dp[i-1])
            dp[i]=dp[i-1];
        answer best2={dp[i].sum-sp[i],dp[i].cnt};
        if(best<best2)
            best=best2;
    }
    return dp[n];
}

long long bin_search(){
    /// (]
    long long st=-1,dr=300000000000000;
    while(dr-st>1){
        long long mij=(st+dr)/2;
        if(get_dp(mij).cnt<k)
            dr=mij;
        else
            st=mij;
    }
    return get_dp(dr).sum+dr*k;
}

int main()
{
    read();
    cout<<bin_search();
    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