Question

ANSWER USING PYTHON

Write a recursive function that takes 2 sorted lists as arguments and returns a single, merged sorted list as a result. For example, if the two input lists are [0, 2, 4, 6, 8] and [1, 3, 5, 7, 9], the returned result should be [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]. Remember that you can add lists in Python using the + operator ([0] + [1,2,3] = [0,1,2,3]) and can take slices of lists with the slice operator (if x = [0, 1, 2, 3, 4], x[1:] = [1, 2, 3, 4]). You could also use the other list methods that are available if you think they are applicable (e.g., pop). Remember to think about the base case(s) and how you will move toward a smaller problem at each step.

Answer 1

########################################PGM START ###################################

def mergeList(l1,l2):

    #if both the list are non empty then

    if l1 and l2:

        #if first element of list 1 greater than first element of list 2

        #swap the first and second list

        if l1[0] > l2[0]:

            l1, l2 = l2, l1

        #return list of smallest elemet + call the merge list funtion with remaining element of list 1 and list 2

        return [l1[0]] + mergeList(l1[1:], l2)

    #finally return combined list l1 and l2 if atleast one of the list is empty

    return l1 + l2

#main function

if __name__=="__main__":

    #list1 and list2

    l1=[0,2,4,6,8]

    l2=[1,3,5,7,9]

    print("List 1 ==> "+str(l1))

    print("List 2 ==> "+str(l2))

    #calling the mergeList funtion with list1 & list 2

    print("Merged List ==> "+str(mergeList(l1,l2)))

############################### PGM END #########################################