coding-challenges/mergeTwoSortedLinkedLists.py at master · AldoFusterTurpin/coding-challenges · GitHub

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# ALDO FUSTER TURPIN
"""
 Merge two linked lists
 head could be None as well for empty list
 Node is defined as

 class Node(object):

   def __init__(self, data=None, next_node=None):
       self.data = data
       self.next = next_node

 return back the head of the linked list in the below method.
"""

def MergeLists(headA, headB):
    newHead = None
    currentNode = None

    #easy end
    if headA is None:
        return headB

    #easy end
    elif headB is None:
        return headA

    #decide the new head
    if (headA and headB):
        if (headA.data <= headB.data):
            currentNode = headA
            headA = headA.next

        else:
            currentNode = headB
            headB = headB.next

    newHead = currentNode

    #create the new sorted linked list
    while((headA is not None) and (headB is not None)):
        if (headA.data <= headB.data):
            currentNode.next = headA
            currentNode = headA
            headA = headA.next
        else:
            currentNode.next = headB
            currentNode = headB
            headB = headB.next

    if (headA is None):
        currentNode.next = headB
    if (headB is None):
        currentNode.next = headA

    return newHead