class Queue:
def __init__(self):
self.__list = DoubleLinkedList()
def enqueue(self, val):
self.__list.add(val)
def dequeue(self):
val = self.__list.front()
self.__list.remove_first()
return val
def is_empty(self):
return self.__list.size == 0
def front(self):
return self.__list.front()
def __len__(self):
return self.__list.size
# my_stack=Stack()
# my_stack.push(1)
# my_stack.push(2)
# my_stack.push(3)
# my_stack.push(5)
# print(my_stack.peek())
# print(len(my_stack))
# print(my_stack.pop())
# print(len(my_stack))
# print(my_stack.peek())
class Stack:
def __init__(self):
self.__list=DoubleLinkedList()
def push(self,val):
self.__list.add(val)
def pop(self):
val = self.__list.back()
self.__list.remove_last()
return val
def is_empty(self):
return self.__list.size==0
def peek(self):
return self.__list.back()
def __len__(self):
return self.__list.size