How To Reverse A Linked List Recursively In Python
Tags: algorithms, career, programming, python
Published: 2024-05-05 11:39:54

In Python interviews, you'll often come across questions regarding reversing linked lists. Let's delve into how to reverse a linked list programmatically using iterative methods in Python.

Welcome back! In this blog post, I'll guide you through the process of recursively finding the inverse of a linked list in Python. Reversing a linked list is a common topic in intermediate-level interviews. Additionally, platforms like LeetCode, Code Ninja, Code Studio, and GFG offer challenges related to sequentially mirroring a linked list for practice. Let's dive in!


![reverse a linked list recursively in python by interviewspreparation.com](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3yt1c3hqqpk7wqp7gzj0.jpg)

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## How can you invert a linked list?
The solution is quite simple: you update each node's next pointer to point to its previous node. This recursive inversion of the linked list is achieved through this mechanism.

Let me delve into how to accomplish "recursively reversing a linked list in Python." If you're not yet familiar with the basic concept, fear not — I'll elucidate it using an animation below. Take a moment to observe the animation, as it will help you visualize how the process operates.

I'll then break down the process of recursively reversing a linked list in Python into four distinct steps. This systematic approach will aid in understanding the concept more effectively and allow for any necessary adjustments.

{% embed https://youtu.be/EEGU66erND4?si=I68dDVimcDtxov03 %}

## Program to Reverse a linked list in Python

Follow [Interviewsprepartion.com](https://interviewspreparation.com/reverse-a-linked-list-recursively/) to get access all steps

```
def reverseList(self, head: ListNode) -> ListNode:
        # solution by interviewspreparation.com

        if not head or not head.next:
            return head

        reversed_head = self.reverseList(head.next)
        
        head.next.next = head
        head.next = None
        
        return reversed_head
```

## Summarizing reverse a linked list recursively program
Understanding the reversal of a linked list involves conceptualizing it as flipping or inverting the sequence of elements within the list. This operation holds significance in the realm of data structures and algorithms, as it enables various manipulations and optimizations.

There are multiple methodologies to achieve list reversal, including iterative, recursive, or paired reversal techniques. Linked lists exist in diverse forms, such as singly linked lists, doubly linked lists, circular linked lists, and sorted linked lists. Paired reversal typically involves swapping adjacent elements, while recursive inversion entails a function calling itself with the next linked list node. Reversing a doubly linked list requires adjusting both the next and previous pointers accordingly.

Furthermore, stacks, another fundamental data structure, can undergo reversal using pop and push operations. Achieving a reversal operation with a time complexity less than O(n) poses a challenge but can be accomplished with certain optimizations.

To hone one's skills in linked list reversal, prominent platforms like LeetCode, GeeksforGeeks, and Code Studio offer a plethora of practice problems. Additionally, Stack Overflow serves as a valuable resource for queries regarding the best approaches to invert linked lists across various programming languages such as Java and C.