Lecture 181:- Inserting in a Linked List

 Sure! Let's implement the insertion functionality in a singly linked list using Python. We'll create methods to insert elements at the beginning, end, and at a specific position in the linked list.

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class Node:    def __init__(self, data):        self.data = data        self.next = None class LinkedList:    def __init__(self):        self.head = None    def append(self, data):        new_node = Node(data)        if not self.head:            self.head = new_node        else:            current = self.head            while current.next:                current = current.next            current.next = new_node    def prepend(self, data):        new_node = Node(data)        new_node.next = self.head        self.head = new_node    def insert_after_node(self, prev_node, data):        if not prev_node:            print("Previous node is not in the linked list.")            return        new_node = Node(data)        new_node.next = prev_node.next        prev_node.next = new_node    def display(self):        current = self.head        while current:            print(current.data, end=" -> ")            current = current.next        print("None") # Example usage: if __name__ == "__main__":    linked_list = LinkedList()    linked_list.append(3)    linked_list.append(7)    linked_list.append(9)    print("Original Linked List:")    linked_list.display()    # Inserting 1 at the beginning    linked_list.prepend(1)    print("Linked List after inserting 1 at the beginning:")    linked_list.display()    # Inserting 5 after node with value 3    prev_node = linked_list.head.next    linked_list.insert_after_node(prev_node, 5)    print("Linked List after inserting 5 after node with value 3:")    linked_list.display()    # Inserting 11 at the end    linked_list.append(11)    print("Linked List after inserting 11 at the end:")    linked_list.display()

In the example above, we have created a LinkedList class and added methods to insert elements at the beginning (prepend), after a specific node (insert_after_node), and at the end (append). We create a linked list with elements 3, 7, and 9. Then, we demonstrate the insertion operations by inserting 1 at the beginning, 5 after the node with value 3, and 11 at the end. We display the linked list after each insertion to see the changes.