Python Program to Print the Alternate Nodes in a Linked List without using Recursion

Python Server Side Programming Programming

When it is required to print the alternate nodes in a linked list without using recursion, a method to add elements to the linked list, a method to display the elements of the linked list, and a method to get the alternate values of a linked list are defined.

Below is a demonstration for the same −

Example

Live Demo

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

class my_linked_list:
   def __init__(self):
      self.head = None
      self.last_node = None

   def add_value(self, my_data):
      if self.last_node is None:
         self.head = Node(my_data)
         self.last_node = self.head
      else:
         self.last_node.next = Node(my_data)
         self.last_node = self.last_node.next

   def print_it(self):
      curr = self.head
      while curr:
         print(curr.data)
         curr = curr.next

   def alternate_nodes(self):
      curr = self.head
      while curr:
         print(curr.data)
         if curr.next is not None:
            curr = curr.next.next
         else:
            break

my_instance = my_linked_list()
my_list = input("Enter the elements of the linked list :").split()
for elem in my_list:
   my_instance.add_value(elem)
print("The alternate elements in the linked list are :")
my_instance.alternate_nodes()

Output

Enter the elements of the linked list :56 78 43 51 23 89 0 6
The alternate elements in the linked list are :
56
43
23
0

Explanation

The ‘Node’ class is created.
Another ‘my_linked_list’ class with required attributes is created.
It has an ‘init’ function that is used to initialize the first element, i.e the ‘head’ to ‘None’ and last node to ‘None’.
Another method named ‘add_value’ is defined, that is used to add data to the linked list.
Another method named ‘print_it’ is defined, that iterates over the list, and prints the elements.
Another method named ‘alternate_nodes’ is defined that is defined that is used to iterate through the linked list.
An object of the ‘my_linked_list’ class is created.
The alternate_nodes method is called, to find the elements in alternative indices.
This output is displayed on the console.

AmitDiwan

Published on 14-Apr-2021 13:18:11

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