Cod sursa(job #772420)

Utilizator vendettaSalajan Razvan vendetta Data 29 iulie 2012 17:09:59
Problema Ferma Scor 50
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.79 kb
#include <iostream>
#include <fstream>
#include <deque>

using namespace std;

ifstream f("ferma.in");
ofstream g("ferma.out");

#define nmax 10005
#define Kmax 1005

int n, K, a[2*nmax], dp[Kmax][2*nmax], s[2*nmax];
deque<int> dq;

void citeste(){

    f >> n >> K;
    for(int i=1; i<=n; i++) f >> a[i], s[i] = s[i-1]+a[i];

    for(int i=n+1; i<=2*n; i++) a[i] = a[i-n], s[i] = s[i-1]+a[i];//dublez vectorul pentru a fi circular
//    for(int i=1; i<=2*n; i++) cout << s[i] << " ";
  //  cout << "\n";
}

int afla_poz(){

    int poz = 0;
    int rez = -2000000000;
    dq.clear();
    int dr = 0;
    for(int i=1; i<=2*n; i++){
        while(dq.size() && i-dq.front()+1 > n) dq.pop_front();//scot secventele mai mari ca si n;
        while(dq.size() && s[i] <= s[dq.back()]) dq.pop_back();//am nevoie de cea mai mica secventa
        dq.push_back(i);
        if (rez < s[i] - s[dq.front()]){
            rez = s[i] - s[dq.front()];
            poz = dq.front() + 1;
            dr = i;
        }
    }
    return poz;

}

void rezolva(){

    //dp[i][j] = productivitate maxima din primele j gaini avand i treceri


    int rez = 0;
    int poz = afla_poz();

    for(int i=0; i<=K; i++){
        for(int j=1; j<=n; j++) dp[i][j] = 0;
    }

    dp[1][poz] = max(0, a[poz]);

    for(int i=1; i<=K; i++){//am i treceri
        for(int j=poz+1; j<=poz+n-1; j++){
            dp[i][j] = dp[i][j-1];
            for(int k=j; k>=poz; k--){//incerc fiecare secventa de genul [j,k]; [j,k-1]; .. [j,poz]
                dp[i][j] = max(dp[i][j], (s[j] - s[k-1]) + dp[i-1][k-1]);
            }
        }
    }

    rez = dp[K][poz+n-1];

    g << rez << "\n";

}

int main(){

    citeste();
    rezolva();

    f.close();
    g.close();

    return 0;

}