Implement Queue using Stacks Python

PROGRAM TO IMPLEMENT QUEUE USING STACKS

class Queue: 

    def __init__(self):

        self.s1 = []

        self.s2 = []

  

    def enQueue(self, x):

          

        # Move all elements from s1 to s2 

        while len(self.s1) != 0: 

            self.s2.append(self.s1[-1]) 

            self.s1.pop()

  

        # Push item into self.s1 

        self.s1.append(x) 

  

        # Push everything back to s1 

        while len(self.s2) != 0: 

            self.s1.append(self.s2[-1]) 

            self.s2.pop()

  

    # Dequeue an item from the queue 

    def deQueue(self):

          

            # if first stack is empty 

        if len(self.s1) == 0: 

            print("Q is Empty")

      

        # Return top of self.s1 

        x = self.s1[-1] 

        self.s1.pop() 

        return x

  

# Driver code 

if __name__ == '__main__':

    q = Queue()

    q.enQueue(1) 

    q.enQueue(2) 

    q.enQueue(3) 

  

    print(q.deQueue())

    print(q.deQueue())

    print(q.deQueue())




OUTPUT:

1
2
3

CREDITS: https://www.geeksforgeeks.org/queue-using-stacks/