Reverse Linked List in Python

Master the art of reversing linked lists in Python and unlock new possibilities in data structures and algorithms.| …

Updated July 11, 2023

|Master the art of reversing linked lists in Python and unlock new possibilities in data structures and algorithms.|

Reverse Linked List in Python: A Comprehensive Guide

Definition:

A linked list is a linear collection of nodes, where each node points to the next one. Reversing a linked list involves changing the direction of the links between nodes, so that the last node becomes the first, and vice versa.

Why Learn How to Reverse Linked Lists in Python?

Reversing linked lists is an essential skill for any Python programmer, as it has numerous applications in data structures, algorithms, and problem-solving. By mastering this technique, you’ll be able to:

Improve your understanding of linked lists and their behavior
Develop a deeper appreciation for recursion and iteration
Enhance your problem-solving skills with creative solutions

Step-by-Step Explanation:

Reversing a linked list in Python involves several steps:

Initialize a pointer to the head node of the original linked list.
Iterate through the list, updating each node’s link to point to the previous node.
Swap the links between nodes, so that each node points to its new neighbor.

Code Snippet: Reversing a Linked List using Iteration

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

def reverse_linked_list(head):
    """
    Reverse a linked list in-place.
    
    Args:
    head (Node): The head node of the original linked list.
    
    Returns:
    Node: The head node of the reversed linked list.
    """
    prev = None
    current = head
    
    while current:
        # Store next node before updating links
        next_node = current.next
        
        # Update current node's link to point to previous node
        current.next = prev
        
        # Move to the next node
        prev = current
        current = next_node
    
    return prev

# Example usage:
head = Node(1)
head.next = Node(2)
head.next.next = Node(3)

reversed_head = reverse_linked_list(head)

print("Reversed Linked List:")
while reversed_head:
    print(reversed_head.value, end=" ")
    reversed_head = reversed_head.next

Code Explanation:

The Node class represents individual nodes in the linked list.
The reverse_linked_list function iterates through the original linked list, updating each node’s link to point to its previous node.
In each iteration, we store the next node before updating the current node’s link. This ensures that the links between nodes are correctly updated.
Finally, we return the head node of the reversed linked list.

Readability Score:

This article aims for a Fleisch-Kincaid readability score of 8-10, making it accessible to a general audience with a high school education or equivalent. The language is clear and concise, avoiding technical jargon whenever possible.

Reverse Linked List in Python