链表_leetcode82

# 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

 dummyHead = ListNode(0)
 dummyHead.next = head
 pre = dummyHead

 curNode = head
 nextNode = curNode.next
 curVal = curNode.val
 unique = True

 while curNode and nextNode:

 if curNode.val == curVal and nextNode.val == curVal:
 unique = False
 curNode = nextNode
 nextNode = nextNode.next
 continue

 if curNode.val == curVal and nextNode.val != curVal and not unique:
 curNode = nextNode
 nextNode = nextNode.next
 curVal = curNode.val
 unique = True
 continue

 else:
 pre.next = curNode
 pre = pre.next

 curNode = nextNode
 nextNode=nextNode.next
 curVal = curNode.val
 unique = True

 if curNode.val == curVal and not unique:
 pre.next = None

 if curNode.val == curVal and unique:
 pre.next = curNode


 return dummyHead.next