Cod sursa(job #1941209)

Utilizator dorin31Geman Dorin Andrei dorin31 Data 27 martie 2017 02:00:16
Problema Statistici de ordine Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 0.76 kb
#include <iostream>
#include <fstream>

#define maxN 3000003

using namespace std;

ifstream fin("sdo.in");
ofstream fout("sdo.out");

int n,k,v[maxN];

int pivot(int left, int right)
{
    int i=left, j=right, x=v[(left+right)/2];

    while (i<j)
    {
        while (i<right && v[i]<x) ++i;
        while (j>left && v[j]>=x) --j;
        if (i<j) swap(v[i],v[j]);
    }
    return i;
}


void quickSelect(int left, int right, int k)
{
    if (left==right) return;

    int x=pivot(left,right);
    int nr=x-left+1;

    if (nr>=k) quickSelect(left,x,k);
    else quickSelect(x+1,right,k-nr);
}

int main()
{
    fin>>n>>k;
    for (int i=1; i<=n; ++i)
        fin>>v[i];
    quickSelect(1,n,k);
    fout<<v[k];
    return 0;
}