Queues
Queues Introduction
- The queue also contains an ordered set of data.
- A queue is a linear data structure that stores data in a First In, First Out (FIFO) manner i.e. the item added earlier gets removed first.
- A queue is an abstract data structure and is open at both ends.
- Queue has three methods namely, Enqueue, dequeue, and peek.
- Queue used in Operating systems like CPU scheduling, disk scheduling, etc as well as used in hardware interrupts.
- Examples of queues are ticket lines, escalators, bookshelf, etc.
Queues Implementation
These are the following methods in queues implementation.
- queue.Enqueue()
- The queue.Enqueue() method adds an element at the rear of the queue.
- queue.Dequeue()
- The queue.Dequeue() method removes an element from the front of the queue.
- queue.Front()
- The queue.Front() method returns the front item from the queue.
- queue.Rear()
- The queue.rear() method returns the rear item from the queue.
- queue.isEmpty()
- The queue.isEmpty() method returns True if the queue is empty, else returns False.
We can implement a queue using a list and using its functions insert and pop.
class Queue:
def __init__(self):
self.queue = []
def isEmpty(self):
return True if len(self.queue) == 0 else False
def front(self):
return self.queue[-1]
def rear(self):
return self.queue[0]
def enqueue(self, x: int):
self.x = x
self.queue.insert(0, x)
def dequeue(self):
self.queue.pop()
