Question

Implementation of dequeue using a one dimensional array as storage element. The program should implement the basic addition, deletion operations. 

Answer 1

Ques .Implementation of dequeue using a one dimensional array as storage element. The program should implement the basic addition, deletion operations. 

Answer : 

Dequeue : Dequeue is also known as Double Ended Queue is also a Queue data structure in which the insertion and deletion operations are performed at both the ends (front and rear). That means, we can insert at both front and rear positions and can delete from both front and rear positions.Double Ended Queue can be represented in two ways:

1. Input Restricted Double Ended Queue - the insertion operation is performed at only one end and deletion operation is performed at both the ends.
2. Output Restricted Double Ended Queue -  the deletion operation is performed at only one end and insertion operation is performed at both the ends.

Examples :

1. Ticket counter line where people who come first will get his ticket first.
2. Bank line where people who come first will done his transaction first.
3. Toilet or Washroom use line 
4. All the lines similar like above.
5. Key press sequence in keyboard.
6. ATM booth line

Program of de-queue :

#creating a deque  def make_dqueue():     dqueue=[]     return dqueue def dequeue_is_empty(dqueue): #when a dequeue is empty its size is 0     return len(dqueue)==0 def enqueue_rear(dqueue,item):# adding element from last     dqueue.append(item) def enqueue_front(dqueue,item):#adding element from front     dqueue.insert(0,item) def dequeue_rear(dqueue):#deleting element from last     dqueue.pop(-1) def dequeue_front(dqueue):#deleting element from front     dqueue.pop(0) def last_element(dqueue):#give the peek element     if (queue_is_Empty(dqueue)):          return str(-maxsize -1)     return dqueue[len(dqueue) - 1]  dqueue = make_dqueue() #adding of element from rear  enqueue_rear(dqueue,1)  print(dqueue) #adding of element from rear enqueue_rear(dqueue,2) print(dqueue) #adding of element from rear enqueue_rear(dqueue,3) print(dqueue) #adding of element from rear enqueue_rear(dqueue,4) print(dqueue) #adding of element from rear enqueue_rear(dqueue,5) print(dqueue) #removal of element from rear dequeue_rear(dqueue) print(dqueue) #removal of element from rear dequeue_rear(dqueue) print(dqueue) #adding of element from front enqueue_front(dqueue,6) print(dqueue) #adding of element from front enqueue_front(dqueue,7) print(dqueue) #adding of element from front enqueue_front(dqueue,8) print(dqueue) #removing element from front dequeue_front(dqueue) print(dqueue) #removing element from front dequeue_front(dqueue) print(dqueue) #printing peek element of dequeue print(last_element(dqueue))

 Output : 

[1]

[1, 2] 

[1, 2, 3] 

[1, 2, 3, 4] 

[1, 2, 3, 4, 5] 

[1, 2, 3, 4] 

[1, 2, 3] 

[6, 1, 2, 3] 

[7, 6, 1, 2, 3] 

[8, 7, 6, 1, 2, 3] 

[7, 6, 1, 2, 3] 

[6, 1, 2, 3] 

3

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