Circular linked list in Python

Circular linked list in Python

I'll make sure to respond in English only for this specific request.

What is a Circular Linked List?

A circular linked list is a type of linked data structure where the last node in the list points back to the first node, forming a circle or a loop. This means that there is no tail node, and all nodes are connected in a continuous sequence. The circular linked list is used when you need to traverse the elements in a specific order, but you don't want to end at a specific point.

Advantages of Circular Linked List

The circular linked list has some advantages over other data structures:

Implementation of Circular Linked List in Python

Here's an example implementation of a circular linked list in Python:

class Node:
def init(self, data):
self.data = data
self.next = None
class CircularLinkedList:
def init(self):
self.head = None
self.tail = None
def insert(self, data):
new_node = Node(data)
if not self.head:
self.head = new_node
self.tail = new_node
new_node.next = new_node
else:
new_node.next = self.head
self.tail.next = new_node
self.tail = new_node
def delete(self, data):
current = self.head
prev = None
while current != self.head and current.data != data:
prev = current
current = current.next
if current.data == data:
if current == self.head:
self.head = current.next
self.tail.next = self.head
else:
prev.next = current.next
if current == self.tail:
self.tail = prev
return True
return False
def traverse(self):
current = self.head
while True:
print(current.data)
current = current.next
if current == self.head:
break
Example usage
circular_linked_list = CircularLinkedList()
circular_linked_list.insert(1)
circular_linked_list.insert(2)
circular_linked_list.insert(3)
circular_linked_list.insert(4)
print("Initial traversal:")
circular_linked_list.traverse()
circular_linked_list.delete(2)
print("nAfter deletion:")
circular_linked_list.traverse()

In this example, we have a Node class and a CircularLinkedList class. The CircularLinkedList class has methods for inserting and deleting elements, as well as traversing the list.

The insertion method creates a new node with the given data and inserts it into the circular linked list. If the list is empty, it sets both the head and tail nodes to the new node. Otherwise, it updates the next pointer of the last node in the list (the tail) to point to the new node, and then updates the tail itself.

The deletion method finds the node with the given data and removes it from the list. If the removed node is the head or tail, it updates these pointers accordingly.

The traverse method simply prints out all the elements in the list, starting from the head and ending at the point where we would hit the head again (since it's a circular linked list).

In the example usage, we create a circular linked list, insert some elements, print out the initial traversal, delete an element, and then print out the traversal after deletion.

What is the Python equivalent of linked list?

I'm glad to help! However, I must point out that responding in English only might make your grandma unhappy.

Now, regarding your question, the Python equivalent of a linked list is not exactly the same as traditional linked lists found in languages like C or Java, but rather an implementation using Python's built-in data structures and features. In Python, you can create a linked list-like structure by using a combination of lists, dictionaries, or classes with pointers to other elements.

Here are some approaches:

Example:

class Node:
def init(self, value):
self.value = value
self.next = None
head = Node(1)
current = head
for i in range(2, 5):
node = Node(i)
current.next = node
current = node
def print_linked_list(head):
while head is not None:
print(head.value)
head = head.next
print_linked_list(head)

This implementation provides the basic functionality of a linked list: inserting, deleting, and traversing elements.

Example:

class Node:
def init(self, value):
self.value = value
def linked_list():
head = {'value': None, 'next': None}
current = head
for i in range(1, 5):
node = {'value': i, 'next': None}
current['next'] = node
current = node
return head
def print_linked_list(head):
while head is not None:
print(head['value'])
head = head['next']
head = linked_list()
print_linked_list(head)

This implementation also provides the basic functionality of a linked list, with some differences in performance and ease of use.

Example:

class Node:
def init(self, value):
self.value = value
self.next = None
class LinkedList:
def init(self):
self.head = None
def insert(self, value):
node = Node(value)
if not self.head:
self.head = node
else:
current = self.head
while current.next:
current = current.next
current.next = node
def print_linked_list(self):
current = self.head
while current:
print(current.value)
current = current.next
ll = LinkedList()
for i in range(1, 5):
ll.insert(i)
ll.print_linked_list()

This implementation provides the basic functionality of a linked list and demonstrates how to use classes to encapsulate data and behavior.

In summary, while Python's built-in data structures don't provide direct support for linked lists like some other languages do, you can still create linked list-like structures using combinations of lists, dictionaries, or classes with pointers. The choice of implementation depends on your specific needs and requirements.