Question

Given two sorted lists, L1 and L2, write a procedure to computeL1 ∪ L2 using only the basic list operations.

Answer 1

function merge (list1, list2)

{

    arr = create new list of size (list1.length + list2.length)

   

    i = 0;

    j = 0;

    index = 0;

   

    // loop until either of the list is completely

// iterated

    while i < list1.length && j < list2.length

    {

        // if the current element of list1 is smaller

        if list1[i] <= list2[j]

        {

            arr[index++] = list1[i]

            i++

        }

        // if the current element of list2 is smaller

        else

        {

            arr[index++] = list2[j]

            j++

        }

    }

   

// traverse through the left over list1

    while i < list1.length

    {

        arr[index++] = list1[i]

        i++

    }

   

// traverse through the left over list2

    while( j < list2.length )

    {

        arr[index++] = list2[j]

        j++

    }

   

    return arr

}