用一個(gè)指針掃描
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def deleteDuplicates(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if not head or not head.next:
return head
p = head
while p:
if p.next:
if p.next.val != p.val:
p = p.next
else:
q = p.next
p.next = q.next
else:
break
return head
