题目来源
https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
题意分析
Input:
:type head: ListNode
Output:
:rtype: ListNode
Conditions:与83题不同，只要元素出现过，则将该元素去掉
题目思路
因为list是有序的，并且可能返回一个空list，所以增加一个头节点。再增加一个节点时，就看这个节点之后是否有值与这个节点的值重复，如果有就不加这个值的【所有】节点
AC代码（Python）
1 # Definition for singly-linked list. 2 # class ListNode(object): 3 # def __init__(self, x): 4 # self.val = x 5 # self.next = None 6 7 class Solution(object): 8 def deleteDuplicates(self, head): 9 """ 10 :type head: ListNode 11 :rtype: ListNode 12 """ 13 if head == None or head.next == None: 14 return head 15 16 ans = ListNode(-1) 17 ans.next = head 18 p = ans 19 temp = p.next 20 21 while p.next: 22 while temp.next and temp.next.val == p.next.val: 23 temp = temp.next 24 if p.next == temp: 25 p = p.next 26 temp = p.next 27 else: 28 p.next = temp.next 29 30 return ans.next 31 32