def pop(self):
if self._head is None:
raise LinkedListUnderflow("in pop of LDList")
e = self._head.elem
self._head = self._head.next
if self._head:
self._head.prev = None
return e
def pop(self): # pop out head element
if self._rear is None:
raise LinkedListUnderflow("in pop of CLList")
p = self._rear.next
if self._rear is p:
self._rear = None
else:
self._rear.next = p.next
return p.elem
def pop_last(self):
if self._head is None:
raise LinkedListUnderflow("in pop_last of LDList")
e = self._rear.elem
self._rear = self._rear.prev
if self._rear is None:
self._head = None # it is empty now
else:
self._rear.next = None
return e
def pop(self):
if self._head is None:
raise LinkedListUnderflow("in pop of LDList")
e = self._head.elem
self._head = self._head.next
if self._head is None:
self._rear = None # it is empty now
else:
self._head.prev = None
return e
def pop_last(self):
if self._head is None: # empty list
raise LinkedListUnderflow("in pop_last")
p = self._head
if p.next is None: # list with only one element
e = p.elem
self._head = None
return e
while p.next.next: # till p.next be last node
p = p.next
e = p.next.elem
p.next = None
return e
def pop(self):
if self._head is None:
raise LinkedListUnderflow("in pop")
e = self._head.elem
self._head = self._head.next
return e