Searching for median and index out of bounds error

I am writing a program that is an altered version of the quick sort to find the median of a set of integers in an array. My first problem is that I have an index out of bounds error that I can't seem to get rid of. Secondly, I'm not sure how u would find the median of the array if the number of elements is even. The program searches based on the index and I don't know how I would go about finding the average of the two elements.

For input the first number is the number of elements, followed by the elements themselves.

3
0
5
4

So 4 should be returned.

Code:

import java.util.*;

public class randoSelect {
    public static void main(String[] args)
    {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] array=new int[N];
    int searchNum=0;
    for(int i=0;i<N;i++)
        {
            array[i]=sc.nextInt();
        }

    if (N%2!=0)
    {
        searchNum=((N-1)/2)+1;
    }
    //System.out.println("searchnum="+searchNum);
    int median = randomizedSelect(array, 0, array.length-1, searchNum);
    System.out.println(median);

    }

    public static int randomizedSelect (int[] array,int p,int r, int i)
    {
        if (p==r)
            return array[p];

        int center = randomizedPartition(array, p, r);
        int k = center-p+1;
        if (k==i)
            return array[center];
        else if (i<k)
            return randomizedSelect(array,p,center-1,i);
        else
            return randomizedSelect(array,center+1,r,i-k);
    }

    public static int randomizedPartition(int[] array, int begin, int end)
    {
        Random num=new Random();
        int index=num.nextInt((end-begin)+1)+begin;
        int pivot=array[index];

        swap(array,array[index], array[end]);
        index=end;

        int i=begin-1;

        for (int j=begin; j<=end-1;j++)
        {
            if (array[j]<=pivot)
            {
                i++;
                swap(array,array[i],array[j]);
            }
        }
        swap(array,array[i+1],array[index]);
        return i+1;
    }

    public static void swap(int[] array, int index1, int index2) 
    {
        int temp=array[index1];
        array[index1]=array[index2];
        array[index2]=temp;
    }

}