链表反转

class :
 def __init__(self,x):
      self.val = x
     self.next = None

def reverse(head):
    if head == None or head.next == None:
        return head
 pre = None
  cur = head
   h = head
 while cur:
      h = cur
      tmp = cur.next
       cur.next = pre
       pre = cur
        cur = tmp
    return h

head = None
tmp = head
for i in xrange(1,10):
    if head == None:
       head = ListNode(i)
       tmp = head
   else:
       tmp.next = ListNode(i)
       tmp = tmp.next
tmp = head
while tmp:
    print tmp.val
   tmp = tmp.next

head = reverse(head)
print '----------'
tmp = head
while tmp:
  print tmp.val
   tmp = tmp.next