def append(self, elem):
if self._head is None: # empty list
self._head = LNode(elem, self._head)
self._rear = self._head
else:
self._rear.next = LNode(elem)
self._rear = self._rear.next
def prepend(self, elem): # add element in the front end
p = LNode(elem)
if self._rear is None:
p.next = p # initiates circle
self._rear = p
else:
p.next = self._rear.next
self._rear.next = p
def append(self, elem):
if self._head is None:
self._head = LNode(elem)
return
p = self._head
while p.next:
p = p.next
p.next = LNode(elem)
def __init__(self, elem, prev=None, next_=None):
LNode.__init__(self, elem, next_)
self.prev = prev
def push(self, elem):
self._top = LNode(elem, self._top)
def prepend(self, elem):
self._head = LNode(elem, self._head)
def prepend(self, elem):
if self._head is None:
self._head = LNode(elem, self._head)
self._rear = self._head
else:
self._head = LNode(elem, self._head)