Cod sursa(job #1659376)

Utilizator andru47Stefanescu Andru andru47 Data 22 martie 2016 10:38:17
Problema Statistici de ordine Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 0.68 kb
#include <bits/stdc++.h>
using namespace std;
int n,k,v[3000000 + 5];
inline void rec(int st,int dr,int pos)
{
    if (st==dr)return ;
    int x = v[st+rand()%(dr-st+1)] , i = st , j = dr;
    while(i<j)
    {
        while(v[i]<=x)
            ++i;
        while(v[j]>x)
            --j;
        if (i<j)swap(v[i],v[j]);
    }
    int posfin = j - st +1;
    if (k>posfin)rec(j+1,dr,k-posfin);
    else rec(st,j,k);
}
int main()
{
    freopen("sdo.in","r",stdin);
    freopen("sdo.out","w",stdout);
    scanf("%d %d\n", &n, &k);
    for (int i = 1; i<=n; ++i)
        scanf("%d", &v[i]);
    srand(time(0));
    rec(1, n, k);
    printf("%d\n", v[k]);
    return 0;
}