from typing import Any class Node: def __init__(self, data: Any): self.data = data self.next = None def __repr__(self) -> str: return f"Node({self.data})" class LinkedList: def __init__(self): self.head = None def __iter__(self) -> Any: node = self.head while node: yield node.data node = node.next def __len__(self) -> int: return len(tuple(iter(self))) def __repr__(self) -> str: return "->".join([str(item) for item in self]) def __getitem__(self, index: int) -> Any: if not 0 <= index < len(self): raise ValueError("list index out of range.") for i, node in enumerate(self): if i == index: return node # Used to change the data of a particular node def __setitem__(self, index: int, data: Any) -> None: if not 0 <= index < len(self): raise ValueError("list index out of range.") current = self.head for i in range(index): current = current.next current.data = data def insert_tail(self, data: Any) -> None: self.insert_nth(len(self), data) def insert_head(self, data: Any) -> None: self.insert_nth(0, data) def insert_nth(self, index: int, data: Any) -> None: if not 0 <= index <= len(self): raise IndexError("list index out of range") new_node = Node(data) if self.head is None: self.head = new_node elif index == 0: new_node.next = self.head # link new_node to head self.head = new_node else: temp = self.head for _ in range(index - 1): temp = temp.next new_node.next = temp.next temp.next = new_node def print_list(self) -> None: # print every node data print(self) def delete_head(self) -> Any: return self.delete_nth(0) def delete_tail(self) -> Any: # delete from tail return self.delete_nth(len(self) - 1) def delete_nth(self, index: int = 0) -> Any: if not 0 <= index <= len(self) - 1: # test if index is valid raise IndexError("List index out of range.") delete_node = self.head # default first node if index == 0: self.head = self.head.next else: temp = self.head for _ in range(index - 1): temp = temp.next delete_node = temp.next temp.next = temp.next.next return delete_node.data def is_empty(self) -> bool: return self.head is None def reverse(self) -> None: prev = None current = self.head while current: # Store the current node's next node. next_node = current.next # Make the current node's next point backwards current.next = prev # Make the previous node be the current node prev = current # Make the current node the next node (to progress iteration) current = next_node # Return prev in order to put the head at the end self.head = prev def main(): linked_list = LinkedList() linked_list.insert_head(input("Inserting 1st at head ").strip()) linked_list.insert_head(input("Inserting 2nd at head ").strip()) print("\nPrint list:") linked_list.print_list() linked_list.insert_tail(input("\nInserting 1st at tail ").strip()) linked_list.insert_tail(input("Inserting 2nd at tail ").strip()) print("\nPrint list:") linked_list.print_list() print("\nDelete head") linked_list.delete_head() print("Delete tail") linked_list.delete_tail() print("\nPrint list:") linked_list.print_list() print("\nReverse linked list") linked_list.reverse() print("\nPrint list:") linked_list.print_list() print("\nString representation of linked list:") print(linked_list) print("\nReading/changing Node data using indexing:") print(f"Element at Position 1: {linked_list[1]}") linked_list[1] = input("Enter New Value: ").strip() print("New list:") print(linked_list) print(f"length of linked_list is : {len(linked_list)}") if __name__ == "__main__": main() 

Inserting 1st at head 10 Inserting 2nd at head 20 Print list: 20->10 Inserting 1st at tail 30 Inserting 2nd at tail 40 Print list: 20->10->30->40 Delete head Delete tail Print list: 10->30 Reverse linked list Print list: 30->10 String representation of linked list: 30->10 Reading/changing Node data using indexing: Element at Position 1: 10 Enter New Value: 50 New list: 30->50 length of linked_list is : 2