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How To Split an Array in half in java

I need to split this array after it is sorted so that it prints something like

A: [8, 7, 6, 5]

B: [4, 3, 2, 1]

I know it might be simple but I cant figure it out. Do I need to do something like x.length / 2 ?

 import java.util.Arrays;


public class RecursiveMerge
{

public static void main(String[] args) {
    // TODO Auto-generated method stub
    int [] x= {8,7,5,6,2,4,3,1};
    System.out.println(Arrays.toString(x));
    System.out.println(Arrays.toString(mergeSort(x)));



}

public static int [] mergeSort (int []a)
{
    if(a.length ==1)
        return a;
    else
    {
    int mid =  a.length/2;
    int [] left =mergeSort(Arrays.copyOfRange(a, 0 , mid ));
    int [] right =mergeSort(Arrays.copyOfRange(a, mid, a.length ));

    mergeSort(left);
    mergeSort(right);

    return merge (left, right);
    }
}
public static int[] merge (int[] left, int[] right)
{
int [] result = new int [left.length + right.length];

int leftPtr=0, rightPtr=0, resultPtr=0;


while(leftPtr < left.length && rightPtr < right.length)
    if (left[leftPtr] < right [rightPtr])
        result[resultPtr++] = left[leftPtr++];
    else
        result[resultPtr++] = right[rightPtr++];
while (leftPtr < left.length)
    result[resultPtr++] = left[leftPtr++];
while (rightPtr <right.length)
    result[resultPtr++] = right[rightPtr++];
return result;

}
}
like image 544
user3012019 Avatar asked Mar 05 '15 21:03

user3012019


People also ask

How do you split an array in Java?

Using the copyOfRange() method you can copy an array within a range. This method accepts three parameters, an array that you want to copy, start and end indexes of the range. You split an array using this method by copying the array ranging from 0 to length/2 to one array and length/2 to length to other.


1 Answers

To make it dynamically, do it based on array length and split it in two:

int [] x= {8,7,5,6,2,4,3,1};
int len = x.length;

int a[] = Arrays.copyOfRange(mergeSort(x), 0, len/2);
int b[] = Arrays.copyOfRange(mergeSort(x), (len/2), len);

System.out.println("A: " + Arrays.toString(a));
System.out.println("B: " + Arrays.toString(b));

Hope it helps.

like image 103
Laerte Avatar answered Sep 18 '22 16:09

Laerte