
class Queue:
def __init__(self):
self.items = []
def isEmpty(self):
return self.items == []
def enqueue(self, item):
self.items.insert(0, item)
def dequeue(self):
return self.items.pop()
def size(self):
return len(self.items)
# 调用
q = Queue()
q.enqueue(1)
q.enqueue(2)
q.enqueue(3)
print(q.size())
print(q.dequeue())
print(q.dequeue())
print(q.dequeue())



