Remove duplicate element from sorted Linked List Python

PROGRAM TO REMOVE DUPLICATES FROM A SORTED LINKED LIST

import math

   

# Link list node 

class Node: 

     

    def __init__(self, data):

         

        self.data = data 

        self.next = None

   

# The function removes duplicates 

# from the given linked list

def removeDuplicates(head): 

     

    # Do nothing if the list consist of

    # only one element or empty 

    if (head == None and

        head.next == None):

        return

     

    # Consturct a pointer

    # pointing towards head

    current = head

     

    # Initalise a while loop till the

    # second last node of the linkedlist

    while (current.next):

         

        # If the data of current and next

        # node is equal we will skip the

        # node between them

        if current.data == current.next.data:

            current.next = current.next.next

             

        # If the data of current and

        # next node is different move

        # the pointer to the next node

        else:

            current = current.next

     

    return

   

# UTILITY FUNCTIONS 

# Function to insert a node at the 

# beginging of the linked list 

def push(head_ref, new_data): 

     

    # Allocate node 

    new_node = Node(new_data) 

               

    # Put in the data 

    new_node.data = new_data 

                   

    # Link the old list off

    # the new node 

    new_node.next = head_ref     

           

    # Move the head to point

    # to the new node 

    head_ref = new_node

     

    return head_ref

   

# Function to print nodes

# in a given linked list 

def printList(node): 

     

    while (node != None): 

        print(node.data, end = " ") 

        node = node.next

       

# Driver code

if __name__=='__main__': 

   

    head = None

     

    head = push(head, 20) 

    head = push(head, 13) 

    head = push(head, 13) 

    head = push(head, 11) 

    head = push(head, 11) 

    head = push(head, 11)                                 

   

    print("List before removal of " 

          "duplicates ", end = "") 

    printList(head) 

   

    removeDuplicates(head) 

   

    print("\nList after removal of " 

          "elements ", end = "") 

           

    printList(head)     




OUTPUT

List before removal of duplicates
11 11 11 13 13 20 
List after removal of elements
11 13 20

CREDITS: https://www.geeksforgeeks.org/remove-duplicates-from-a-sorted-linked-list/