82. Remove Duplicates from Sorted List II Leetcode Python

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.

这题的做法是用两个指针pre cur

1.dummy.next= head

2.pre=dummy cur=dummy,next

3.当 指针移到 pre.next 和cur.next 不等的位置 将这个位置加入到 pre.next中去

4.否者就跳过cur

一次遍历 时间是O(n)

代码如下# Definition for singly-linked list.# class ListNode:#def __init__(self, x):#self.val = x#self.next = Noneclass Solution:# @param head, a ListNode# @return a ListNodedef deleteDuplicates(self, head):if head==None or head.next==None:return headdummy=ListNode(0)dummy.next=headpre=dummycur=dummy.nextwhile cur!=None:while cur.next and cur.next.val==pre.next.val:cur=cur.nextif pre.next==cur:pre=pre.nextelse:pre.next=cur.nextcur=cur.nextreturn dummy.next

，不义而富且贵，于我如浮云。