1

class LNode:
def __init__(self,elem,next=None):
self.elem=elem
self.next=next
class List:
def __init__(self):
self.head=LNode(0)
def is_empty(self):
return self.head.next is None
def append(self,elem):
if self.is_empty():
p=LNode(elem)
self.head.next = p
self.head.elem +=1
else:
p = LNode(elem)
p.next = self.head.next
self.head.next = p
self.head.elem += 1
def pop(self,pos):
if pos==0:
print"can not remove head!"
return
else:
p = self.head
q = self.head
for i in range(pos):
p=q
q=q.next
p.next = q.next
self.head.elem -=1
def counts(self):
return self.head.elem
p = List()
p.append(1)