# Queue with 2 stack implementation

# Author: Pradeep K. Pant, ppant@cpan.org

# Problem Statement: Given the Stack class below, implement a Queue class using two stacks!

# create a class

class QueueWith2Stack(object):

# Initialize class

def __init__(self):

# initialize two empty stack using python list which we have to use to implement queue

self.stack1 = []

self.stack2 = []

# Append a element

def enqueue(self,element):

# add a element in the queue

print ("Appending",+element)

self.stack1.append(element)

return True

# take the element out

def dequeue(self):

# remove a element from the queue

# Check for empty

if not self.stack2:

while self.stack1:

# Append in second stack the valu of pop from first list

# reverse order continuous popping of the element

self.stack2.append(self.stack1.pop())

print ("Poping element")

return self.stack2.pop()

# Test set 1

# Create a object of the class

qObj = QueueWith2Stack()

# Add an element

qObj.enqueue(1)

# Add another element

qObj.enqueue(2)

# Add more element

qObj.enqueue(4)

# Add more element

qObj.enqueue(8)

# Remove item

print (qObj.dequeue())

# Remove item

print (qObj.dequeue())

# Remove item

print (qObj.dequeue())

# Remove item

print (qObj.dequeue())

# Test set 2

for i in range(5):

qObj.enqueue(i)

for i in range(5):

print (qObj.dequeue())