Queue Using Linked List in Python
Implementation of Queue Using Linked List in Python
Discover on how implementation of Queue linked list in Python. Queues are essential for managing data in a first-in, first-out (FIFO) manner. This Python implementation provides a solid foundation for understanding queues and their practical use in your programming projects.
In this page, we will delve into the implementation of a queue using a linked list in python, exploring the concepts, benefits, and potential use cases.
Basic Operations on Linked Lists
There are two basic Operations for implementing queue in the linked list. The operations are Insertion and Deletion.
Syntax of Insertion in Linked List
class Node:
def __init__(self, data):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def insert_at_position(self, data, position):
new_node = Node(data)
# Insertion logic here
# Example usage
linked_list = LinkedList()
linked_list.insert_at_position(1, 0)
Syntax of Deletion in Linked List
class Node:
def __init__(self, data):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def insert_at_end(self, data):
new_node = Node(data)
if not self.head:
self.head = new_node
return
current = self.head
while current.next:
current = current.next
current.next = new_node
def delete_by_value(self, value):
if not self.head:
return
if self.head.data == value:
self.head = self.head.next
return
current = self.head
prev = None
while current:
if current.data == value:
prev.next = current.next
return
prev = current
current = current.next
You can perform deletion using the following methods:
- Delete Value
linked_list = LinkedList() linked_list.insert_at_end(1) linked_list.insert_at_end(2) linked_list.insert_at_end(3) value_to_delete = 2 linked_list.delete_by_value(value_to_delete)
Implementation of Queue Using Linked List
Implementing a queue using a linked list allows to grow queue according to the requirements.
A queue implemented using a linked list not changes its behavior and will continue to work according to FIFO.
Code for implementing queue in linked list
class Node:
def __init__(self, data):
self.data = data
self.next = None
class Queue:
def __init__(self):
self.front = None
self.rear = None
def is_empty(self):
return self.front is None
def enqueue(self, data):
new_node = Node(data)
if self.rear is None:
self.front = self.rear = new_node
return
self.rear.next = new_node
self.rear = new_node
def dequeue(self):
if self.is_empty():
return None
temp = self.front
self.front = temp.next
if self.front is None:
self.rear = None
return temp.data
def peek(self):
if self.is_empty():
return None
return self.front.data
def display(self):
current = self.front
while current:
print(current.data, end=" ")
current = current.next
print()
queue = Queue()
queue.enqueue(10)
queue.enqueue(20)
queue.enqueue(30)
print("Queue elements:")
queue.display()
print("Dequeue:", queue.dequeue())
print("Dequeue:", queue.dequeue())
print("Front of the queue:", queue.peek())
print("Is the queue empty?", queue.is_empty())
Explanation
In this implementation, we have a ‘Node’ class to create individual nodes for the linked list and a ‘Queue’ class to implement the queue using a linked list. The ‘Queue’ class has methods for enqueuing, dequeuing, peeking at the front element, checking if the queue is empty, and displaying its contents. The example usage section demonstrates how to use these methods to manipulate the queue.
Use Cases and Applications
Linked lists find application in various domains, such as:
- Memory Management: Allocating and deallocating memory blocks efficiently.
- Graphs: Representing graphs and networks with dynamic connectivity.
- Polynomials: Storing and performing operations on polynomial expressions.
Conclusion
In this comprehensive guide, we’ve explored the world of linked lists, from their fundamental structure to advanced operations and real-world applications. Armed with this knowledge, you’re now better equipped to make informed decisions when implementing linked lists in your programming endeavors. Remember, linked lists are just one of the many tools in your data structure arsenal, each serving a unique purpose in the grand landscape of computer science.
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