Submission #731508

#	Time	Username	Problem	Language	Result	Execution time	Memory
731508		mohav48173	Feast (NOI19_feast)	C++14	100 / 100	278 ms	8068 KiB

feast

#include<bits/stdc++.h>
using namespace std;
int n,k;
long long a[400000];
long long m[400000];
long long mincnt=0;
long double score=0;
long double get(int ind) {
    if(ind<0)return 0;
    else return m[ind];
}
void calc(long double lam) {
    long double bestscore=0;
    long long bestcnt=0;
    long double bestnxt=-lam;
    long long nxtcnt=0;
    for(int i=0;i<n;i++) {
        if(bestscore-lam-get(i-1)>bestnxt ||
           (bestscore-lam-get(i-1)==bestnxt && nxtcnt>bestcnt)) {
            bestnxt=bestscore-get(i-1)-lam;
            nxtcnt=bestcnt;
        }
        if(bestnxt+get(i)>bestscore || (bestnxt+get(i)==bestscore && nxtcnt+1<bestcnt)) {
            bestscore=bestnxt+get(i);
            bestcnt=nxtcnt+1;
        }
    }
    mincnt=bestcnt;
    score=bestscore;
}
int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n>>k;
    for(int i=0;i<n;i++)cin>>a[i];
    m[0]=a[0];for(int i=1;i<n;i++)m[i]=m[i-1]+a[i];
    long double l=0,r=1e18;
    while((r-l)>(long double)(1e-7)) {
        long double mid=(l+r)/2.0;
        calc(mid);
        if(mincnt<=k)r=mid;
        else l=mid;
    }
    calc(r);
    cout<<(long long)(round(score+k*r))<<endl;
    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