How do I reverse a linked list in Python?

How do I reverse a linked list in Python?

To reverse a linked list in Python, you can use an iterative approach or a recursive approach. Which one would you like to see?

Can you show me the iterative approach?

Sure! Here's a simple iterative method:

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

class LinkedList:
    def __init__(self):
        self.head = None

    def reverse(self):
        prev = None
        current = self.head
        while current:
            next_node = current.next  # Store next node
            current.next = prev  # Reverse the link
            prev = current  # Move prev to current
            current = next_node  # Move to next node
        self.head = prev  # Update head to new first element

What if I want to reverse it recursively?

For a recursive approach, you can use the following code:

def reverse_recursive(self, node):
    if node is None or node.next is None:
        return node
    new_head = self.reverse_recursive(node.next)
    node.next.next = node
    node.next = None
    return new_head

Thanks! How do I call these methods?

You can call these methods by creating an instance of LinkedList, adding nodes, and then calling reverse() or reverse_recursive(head) on the list.