Merge_linked_list.py

# Python3 program merge two sorted linked 
# in third linked list using recursive. 

# Node class 
class Node: 
	def __init__(self, data): 
		self.data = data 
		self.next = None


# Constructor to initialize the node object 
class LinkedList: 

	# Function to initialize head 
	def __init__(self): 
		self.head = None

	# Method to print linked list 
	def printList(self): 
		temp = self.head 
		
		while temp : 
			print(temp.data, end="->") 
			temp = temp.next

	# Function to add of node at the end. 
	def append(self, new_data): 
		new_node = Node(new_data) 
		
		if self.head is None: 
			self.head = new_node 
			return
		last = self.head 
		
		while last.next: 
			last = last.next
		last.next = new_node 


# Function to merge two sorted linked list. 
def mergeLists(head1, head2): 

	# create a temp node NULL 
	temp = None

	# List1 is empty then return List2 
	if head1 is None: 
		return head2 

	# if List2 is empty then return List1 
	if head2 is None: 
		return head1 

	# If List1's data is smaller or 
	# equal to List2's data 
	if head1.data <= head2.data: 

		# assign temp to List1's data 
		temp = head1 

		# Again check List1's data is smaller or equal List2's 
		# data and call mergeLists function. 
		temp.next = mergeLists(head1.next, head2) 
		
	else: 
		# If List2's data is greater than or equal List1's 
		# data assign temp to head2 
		temp = head2 

		# Again check List2's data is greater or equal List's 
		# data and call mergeLists function. 
		temp.next = mergeLists(head1, head2.next) 

	# return the temp list. 
	return temp 


# Driver Function 
if __name__ == '__main__': 

	# Create linked list : 
	# 10->20->30->40->50 
	list1 = LinkedList() 
	list1.append(10) 
	list1.append(20) 
	list1.append(30) 
	list1.append(40) 
	list1.append(50) 

	# Create linked list 2 : 
	# 5->15->18->35->60 
	list2 = LinkedList() 
	list2.append(5) 
	list2.append(15) 
	list2.append(18) 
	list2.append(35) 
	list2.append(60) 

	# Create linked list 3 
	list3 = LinkedList() 

	# Merging linked list 1 and linked list 2 
	# in linked list 3 
	list3.head = mergeLists(list1.head, list2.head) 

	print(" Merged Linked List is : ", end="") 
	list3.printList()