Question

Python:

Solve following problems using Linked List Data Structure

2. Create a Queue class. In the queue class create enqueue, dequeue, first, empty, len and resize methods. The class should support circular queue and have the ability to resize the queue.

Answer 1

ANS:

# Online Python compiler (interpreter) to run Python online.
# Write Python 3 code in this online editor and run it.

class Node:
def __init__(self):
self.item=None
self.linked=None
class CQueue:
def __init__(self):
front=None
rear=None

#This is enqueue which will make circular queue

def Enqueue(q,value):
temp=Node()
temp.item=value
  
if(q.front==None):
q.front=temp
else:
q.rear.linked=temp
  
q.rear=temp
q.rear.linked=q.front

#deleting element from Circular queue

def Dequeue(q):
if(q.front==None):
print("Queue Empty!")
return -1000
value=None
if(q.front==q.rear):
  
value=q.front.item
q.front=None
q.rear=None
else:
temp=q.front
value=temp.item
q.front=q.front.linked
q.rear.linked=q.front
  
return value
  
def first(q):
return q.front

def display(q):
temp=q.front
print("Circular Queue Elements:")
  
while(temp.linked!=q.front):
print(temp.item, end=" ")
temp=temp.linked
print(temp.item)
  
if __name__ == '__main__':
q = CQueue()
q.front = q.rear = None

Enqueue(q, 20)
Enqueue(q, 18)
Enqueue(q, 9)
Enqueue(q,12)
  
#print("First=",first(q))
  
  
display(q)
  
print("Deleted value = ", Dequeue(q))
print("Deleted value = ", Dequeue(q))
  

display(q)
  
Enqueue(q, 100)
Enqueue(q, 80)
display(q)

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