def top(self):
if self.is_empty():
raise Empty("Stack is empty")
if self._maxlen is not None:
return self._data[self._current - 1]
else:
return self._data[-1]
def pop(self):
if self._head is None:
raise Empty("Stack is empty")
e = self._head._element
self._head = self._head._next
self._size -= 1
return e
def dequeue(self):
if self.is_empty():
raise Empty("Queue is empty")
answer = self._data[self._front]
self._data[self._front] = None
self._front = (self._front + 1) % len(self._data)
self._size -= 1
return answer
def dequeue(self):
if self._head is None:
raise Empty("Queue is empty")
r = self._head._element
self._head = self._head._next
self._size -= 1
if self.is_empty():
self._tail = None
return r
def dequeue(self):
if self.is_empty():
raise Empty("Queue is empty")
oldhead = self._tail._next
if self._size == 1:
self._tail = None
else:
self._tail._next = oldhead._next
self._size -= 1
return oldhead._element
def first(self):
if self.is_empty():
raise Empty("Queue is empty")
return self._data[self._front]
def pop(self):
if self.is_empty():
raise Empty("Stack is empty")
return self._data.pop()
def top(self):
if self._head is None:
raise Empty("Stack is empty")
return self._head._element
def delete_last(self):
if self.is_empty():
raise Empty("Deque is empty")
return self._delete_node(self._tailer._prev)
def delete_first(self):
if self.is_empty():
raise Empty("Deque is empty")
return self._delete_node(self._header._next)
def last(self):
if self.is_empty():
raise Empty("Deque is empty")
return self._tailer._prev._element
def first(self):
if self.is_empty():
raise Empty("Deque is empty")
return self._header._next._element
def first(self):
if self.is_empty():
raise Empty("Queue is empty")
head = self._tail._next
return head._element