Skip to main content

Write Reverse Linked List in Python

 Reversing a linked list is a common problem in data structures, which involves changing the direction of the links between nodes so that the list's head becomes the tail and vice versa. Here, I will provide a Python implementation for reversing a singly linked list.


Firstly, I'll define the Node class, which represents each element in the list, and then I'll define a LinkedList class which includes a method to reverse the list.







Explanation:

Node Class:

  •     Each node has a data field and a next pointer to the next node in the list.

LinkedList Class:

  •     The append method adds a new node to the end of the list.
  •     The print_list method prints all the nodes in the list from head to tail.
  •     The reverse method changes the pointers' directions:
                   -  We keep track of three pointers: prev for the previous node, current for the current node,                          and next_node for storing the next node temporarily.

                  -  Loop through each node, adjusting the next pointer to point back to the previous node                                 until all nodes are reversed.

                   - Finally, reset the list's head to the last node processed, which is stored in prev.

This basic implementation provides a good starting point for understanding how to manipulate pointers in a linked list to reverse its order.

Comments

Post a Comment

Popular posts from this blog

Django pk vs id

 Django pk VS id If you don’t specify primary_key=True for any fields in your model, Django will automatically add an IntegerField to hold the primary key, so you don’t need to set primary_key=True on any of your fields unless you want to override the default primary-key behavior. The primary key field is read-only. If you change the value of the primary key on an existing object and then save it, a new object will be created alongside the old one Example: class UserProfile ( models . Model ): name = models . CharField ( max_length = 500 ) email = models . EmailField ( primary_key = True ) def __str__ ( self ): return self . name suppose we have this model. In this model we have make email field as primary key. now django default primary key id field will be gone. It'll remove from database. we can not query as   UserProfile.objects.get(id=1) after make email as primary key this query will throw an error.  Now we have to use pk  Us...
Post a Comment
Read more

WSGI vs ASGI: What Every Django Developer Should Know !

  If you've been developing with Django, you've probably come across WSGI (Web Server Gateway Interface), the trusted friend of all traditional, synchronous web apps. But in this fast-moving, real-time world, you may have also heard about its dynamic, asynchronous cousin ASGI (Asynchronous Server Gateway Interface). WSGI (Web Server Gateway Interface): 1. The OG (original) Django interface, designed for synchronous HTTP requests. 2. Perfect for blogs, CMS, e-commerce, and standard web apps. 3. Uses servers like Gunicorn or uWSGI. 4. Limited to handling one request at a time. ASGI (Asynchronous Server Gateway Interface): 1. The modern, scalable interface designed for asynchronous web apps. 2. Ideal for handling WebSockets, HTTP/2, and real-time features like chat apps. 3. Built for high concurrency; uses Uvicorn, Daphne, or similar ASGI servers. 4. Allows you to leverage Python’s async and await for non-blocking code. When to Choose What: WSGI: Traditional apps where synchronou...
Post a Comment
Read more

Importance JWT and How Do JWTs Work in Django

Importance of JWT JWT (JSON Web Token) is a form of transmitting a JSON object as information between parties. Let's learn more about what JWTs are and how they work. JWTs are important for two main reasons: 1. Authorization 2. Information exchange JSON Web Token comprises 3 strings separated by “.” as follows where each part is encoded with base64url encoding : “eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyb2xlIjp7ImlkIjoiNTlhZDFmZTI0MDVkNzk0YTFkYWQ2YmFkIiwiZGlzcGxheV9uYW1lIjoiQWRtaW4iLCJyb2xlX3R5cGUiOiJhZG1pbiJ9LCJpZCI6IlwiNTliYmJjODc0MDVkNzk0NjYwNGEzZjUyXCIiLCJlbWFpbCI6Imp5b3RpZ2F1dGFtMTA4QGdtYWlsLmNvbSJ9.oGA-goFi7ee6DdKn0Z4sctomaY6Ki0mfuJfxT4OK9WA” 1. Header 2. Payload 3. Signature Header: The header contains:      t ype: the specification that the token is a JWT      algorithm: the signing algorithm used to sign said token Algorithms that are used to sign include RSA, HMAC, or SHA256. The signatures for the tokens serve two purposes – integrity ...
Post a Comment
Read more