Queues

FIFO Concept, first in is the first out

Time Complexity of a Queue

Operation	Running Time (Average)	Running Time (Worst)
Access	O (n)	O (n)
Search	O (n)	O (n)
Insertion	O (1)	O (1)
Deletion	O (1)	O (1)

Regular Array Implmentation:

Circular Array Implmentation:

inserting an Image

Deque Data Structure:

Let’s add a Deque Data Structure

class Deque:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def addFront(self, item):
        self.items.append(item)

    def addRear(self, item):
        """ add to rear"""
        self.items.insert(0,item)

    def removeFront(self):
        return self.items.pop()

    def removeRear(self):
        return self.items.pop(0)

    def size(self):
        return len(self.items)
    
    def _print(self):
        '''print Deque Values'''
        return self.items
        