Cod sursa(job #3199524)

Utilizator Bianca2507Negret Bianca Bianca2507 Data 1 februarie 2024 19:22:59
Problema Statistici de ordine Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 kb
#include <fstream>
#include <algorithm>
#include <ctime>
#include <cstdlib>
using namespace std;
ifstream cin("sdo.in");
ofstream cout("sdo.out");
int v[3000005],n,k;
int quickselect(int st,int dr)
{
    if(st==dr)
        return v[st];
    else if(st<dr)
    {
        int p=rand()%(dr-st+1)+st;
        int i=st;
        int j=dr;
        int mod=0;
        swap(v[st],v[p]);
        while(i<j)
        {
            if(v[i]>v[j])
            {
                swap(v[i],v[j]);
                mod=1-mod;
            }
            i=i+mod;
            j=j-(1-mod);
        }
        ///elementul pivot a fost plasat pe pozitia i
        if(i==k)
            return v[i];
        if(k<i)
            quickselect(st,i-1);
        else if(i<k)
            quickselect(i+1,dr);
    }
}
int main()
{
    srand(time(NULL));
    cin>>n>>k;
    for(int i=1; i<=n; i++)
        cin>>v[i];

    cout<<quickselect(1,n);
    return 0;
}