def reverse(head):
if head == None or head.next == None:
return head
psuhead = ListNode(-1)
while head:
nexthead = head.next
head.next = psuhead.next
psuhead.next = head
head = nexthead
head = psuhead.next
del psuhead
return head
def reverse(head):
if head == None or head.next == None:
return head
psuhead = ListNode(-1)
while head:
nexthead = head.next
head.next = psuhead.next
psuhead.next = head
head = nexthead
head = psuhead.next
del psuhead
return head