class Queue:
    def __init__(self):
        self.stack_a = Stack()
        self.stack_b = Stack()

    def EnQueue(self, data):
        self.statck_a.Push(data)

    def DeQueue(self):
        if self.stack_b.IsEmpty():
            self.stack_a.Lock()
            for data in self.stack_a:
                self.stack_b.Push(data)
            self.stack_a.UnLock()

        return self.stack_b.Pop()


class Stack:
    def __init__(self):
        self.queue_a = Queue()
        self.queue_b = Queue()

    def Push(self, data):
        self.queue_a.EnQueue(data)

    def Pop(self):
        if self.queue_b.IsEmpty():
            self.queue_a.Lock()
            for i in range(self.queue_b.Length()):
                self.queue_b.EnQueue(self.queue_a.GetHead())
            self.queue_b.UnLock()

        return self.queue_b.GetTail()

conversion between queue and stack

conversion between queue and stack

C