Cod sursa(job #2113580)

Utilizator sebi110Ciobanu Sebastian sebi110 Data 24 ianuarie 2018 19:29:07
Problema Statistici de ordine Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.84 kb
#include <fstream>
#include <ctime>
#include <cstdlib>
using namespace std;
ifstream f("sdo.in");
ofstream g("sdo.out");
int a[3000005],k;
int part(int st,int dr)
{
    int piv=a[st + (rand()%(dr-st+1))];
    st--;dr++;
    while(1)
    {
        do{
            st++;
        }while(a[st]<piv);
        do{
            dr--;
        }while(a[dr]>piv);
        if(st<dr)
            swap(a[st],a[dr]);
        else
            return dr;
    }
    return 0;
}
void mergesort(int st,int dr)
{
    int mij;
    if(st>=dr)
        return ;
    mij=part(st,dr);
    if(mij>=k)
    {
        mergesort(st,mij);
        return ;
    }
    mergesort(mij+1,dr);
}
int main()
{
    srand(time(NULL));
    int n,i;
    f>>n>>k;
    for(i=1;i<=n;i++)
        f>>a[i];
    mergesort(1,n);
    g<<a[k]<<'\n';
    return 0;
}