Software & Finance





Java - Union of Two Arrays





Here is the Java source code for union of two arrays which means finding the union of elements between two arrays. The good thing about this coding is it will allocate only the required memory. During the first iterator it will count how many number of unique elements are available in two arrays. Then use the formula

"array1 unique count + array2 unique count - intersection of array1 and array2 elements count"

to allocate the memory and fill in the elements in its second iteration.

 

Source Code


import java.io.*;

 

 

class Union

{

    static int[] Find_Common_Elements(int[] p1, int[] p2)

    {

        int count = 0;

        for (int i = 0; i < p1.length; i++)

        {

            for (int j = 0; j < p2.length; j++)

            {

                if (p1[i] == p2[j])

                {

                    count++;

                    break;

                }

            }

        }

 

        int[] result = new int[count];

        count = 0;

        for (int i = 0; i < p1.length; i++)

        {

            for (int j = 0; j < p2.length; j++)

            {

                if (p1[i] == p2[j])

                {

                    result[count++] = p1[i];

                    break;

                }

            }

        }

 

        return result;

    }

 

    static int[] Union_Array(int[] p1, int[] p2)

    {

        int[] temp = Find_Common_Elements(p1, p2);

        int count = p1.length + p2.length - temp.length;

        int[] result = new int[count];

        count = 0;

 

        for (int i = 0; i < p1.length; i++)

            result[count++] = p1[i];

 

        for (int j = 0; j < p2.length; j++)

        {

            boolean bInclude = true;

            for (int k = 0; k < temp.length; k++)

            {

                if (temp[k] == p2[j])

                {

                    bInclude = false;

                    break;

                }

            }

            if (bInclude == true)

                result[count++] = p2[j];

        }

 

        return BubbleSort(result);

    }

 

    static int[] BubbleSort(int[] numarray)

    {

        int max = numarray.length;

        for (int i = 1; i < max; i++)

        {

            for (int j = 0; j < max - i; j++)

            {

 

                if (numarray[j] > numarray[j + 1])

                {

                    int temp = numarray[j];

                    numarray[j] = numarray[j + 1];

                    numarray[j + 1] = temp;

                }

            }

        }

        return numarray;

    }

 

    static int[] Find_Unique_Elements(int[] numarray)

    {

 

        BubbleSort(numarray);

        int element = numarray[0];

        int count = 1;

        for (int i = 1; i < numarray.length; i++)

        {

            if (element == numarray[i])

                continue;

            else

            {

                element = numarray[i];

                count++;

            }

        }

 

        int[] result = new int[count];

 

        count = 0;

        element = numarray[0];

        result[count++] = element;

        for (int i = 1; i < numarray.length; i++)

        {

            if (element == numarray[i])

                continue;

            else

            {

                element = numarray[i];

                result[count++] = element;

            }

        }

        return result;

    }

 

      public static void main(String[] args)

    {

        int[] array1 = new int[] { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100,

             95, 85, 75, 65, 55, 45, 35, 25, 15, 05,

             10, 15, 20, 25, 30, 35, 40, 45, 50, 55

        };

 

        int[] array2 = new int[] { 15, 25, 35, 45, 55,

             12, 22, 32, 43, 52,

             15, 25, 35, 45, 55

        };

 

        int [] p1 = Find_Unique_Elements(array1);

        int [] p2 = Find_Unique_Elements(array2);

        //int [] result = Find_Common_Elements(array1, array2);

        int[] result = Union_Array(p1, p2);

 

        System.out.print("\n\nUnique Sorted Elements in Array1: ");

        for(int i = 0; i < p1.length; i++)

                  System.out.print(p1[i] + " ");

            System.out.print("\n\nUnique Sorted Elements in Array2: ");

        for(int i = 0; i < p2.length; i++)

                  System.out.print(p2[i] + " ");

            System.out.print("\n\nUnion of Elements in Array1 and Array2: ");

        for(int i = 0; i < result.length; i++)

                  System.out.print(result[i] + " ");

            System.out.println();

    }

}

 

Output