Python 不使用堆栈的反向队列
函数reversequeue返回的“Nonetype”对象没有属性值。我不知道该怎么做 当我测试q.front()时。它返回正确的答案。我试图通过声明如果self.head==None来捕捉错误,然后跳过它 在这种情况下我该怎么办Python 不使用堆栈的反向队列,python,python-3.x,queue,reverse,Python,Python 3.x,Queue,Reverse,函数reversequeue返回的“Nonetype”对象没有属性值。我不知道该怎么做 当我测试q.front()时。它返回正确的答案。我试图通过声明如果self.head==None来捕捉错误,然后跳过它 在这种情况下我该怎么办 请帮忙。非常感谢你 您的函数reversequeue(q)没有return语句 class Node: def __init__(self, value): self.value = value self.next = None
请帮忙。非常感谢你 您的函数
reversequeue(q)
没有return
语句
class Node:
def __init__(self, value):
self.value = value
self.next = None
def __str__(self):
return "Node({})".format(self.value)
__repr__ = __str__
class Queue:
def __init__(self):
self.head=None
self.tail=None
def __str__(self):
temp=self.head
out=[]
while temp:
out.append(str(temp.value))
temp=temp.next
out=' '.join(out)
return ('Head:{}\nTail:{}\nQueue:{}'.format(self.head,self.tail,out))
__repr__=__str__
def isEmpty(self):
#write your code here
return (self.head == None) and (self.tail == None)
def __len__(self):
#write your code here
current = self.head
len = 0
while current:
len += 1
current = self.head.next
if self.head.next == self.tail:
break
return len
def enqueue(self, value):
#write your code here
node = Node(value)
if self.isEmpty():
self.head = node
self.tail = node
else:
self.tail.next = node
self.tail = node
def dequeue(self):
#write your code here
if self.isEmpty():
return 'Queue is empty'
else:
popped = self.head.value
self.head = self.head.next
return popped
def front(self):
if self.head != None:
return self.head.value
q = Queue()
def reversequeue(q):
if q.isEmpty() == False:
data = q.front()
q.dequeue()
reversequeue(q)
q.enqueue(data)
def QueuePalindrome(word):
q = Queue()
for i in word:
q.enqueue(i)
p = reversequeue(q)
return p
因此,它默认返回None
。只需为基本情况和递归情况添加一个返回值,然后更新q
:
def reversequeue(q):
if q.isEmpty() == False:
data = q.front()
q.dequeue()
reversequeue(q)
q.enqueue(data)
您的函数
reversequeue(q)
没有return
语句
class Node:
def __init__(self, value):
self.value = value
self.next = None
def __str__(self):
return "Node({})".format(self.value)
__repr__ = __str__
class Queue:
def __init__(self):
self.head=None
self.tail=None
def __str__(self):
temp=self.head
out=[]
while temp:
out.append(str(temp.value))
temp=temp.next
out=' '.join(out)
return ('Head:{}\nTail:{}\nQueue:{}'.format(self.head,self.tail,out))
__repr__=__str__
def isEmpty(self):
#write your code here
return (self.head == None) and (self.tail == None)
def __len__(self):
#write your code here
current = self.head
len = 0
while current:
len += 1
current = self.head.next
if self.head.next == self.tail:
break
return len
def enqueue(self, value):
#write your code here
node = Node(value)
if self.isEmpty():
self.head = node
self.tail = node
else:
self.tail.next = node
self.tail = node
def dequeue(self):
#write your code here
if self.isEmpty():
return 'Queue is empty'
else:
popped = self.head.value
self.head = self.head.next
return popped
def front(self):
if self.head != None:
return self.head.value
q = Queue()
def reversequeue(q):
if q.isEmpty() == False:
data = q.front()
q.dequeue()
reversequeue(q)
q.enqueue(data)
def QueuePalindrome(word):
q = Queue()
for i in word:
q.enqueue(i)
p = reversequeue(q)
return p
因此,它默认返回None
。只需为基本情况和递归情况添加一个返回值,然后更新q
:
def reversequeue(q):
if q.isEmpty() == False:
data = q.front()
q.dequeue()
reversequeue(q)
q.enqueue(data)
问题是函数返回q.front()是非类型问题是函数返回q.front()是非类型