Cod sursa(job #1221208)

Utilizator acomAndrei Comaneci acom Data 19 august 2014 21:03:44
Problema Statistici de ordine Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include<cstdio>
#include<cstdlib>
#include<ctime>
using namespace std;
#define NMAX 3000005
int n,k,aux,v[NMAX];
int poz(int st, int dr)
{
    int ii=0,jj=1,p=st+rand()%(dr-st+1);
    aux=v[p], v[p]=v[st], v[st]=aux;
    while (st<dr)
    {
        if (v[st]>v[dr])
        {
            aux=v[st], v[st]=v[dr], v[dr]=aux;
            aux=ii, ii=jj, jj=aux;
        }
        st+=ii, dr-=jj;
    }
    return st;
}
int sdo()
{
    int st=1,dr=n,p;
    while (st<dr)
    {
        p=poz(st,dr);
        if (p==k)
            return v[k];
        if (p>k)
            dr=p-1;
        else
            st=p+1;
    }
    return v[st];
}
int main()
{
    int i;
    freopen("sdo.in","r",stdin);
    freopen("sdo.out","w",stdout);
    srand(time(0));
    scanf("%d%d",&n,&k);
    for (i=1;i<=n;++i)
        scanf("%d",&v[i]);
    printf("%d\n",sdo());
    return 0;
}