Leetcode "Remove duplicates from Sorted List II" Python implementation

title :

Given a sorted linked list, delete all nodes that has 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 .

code : OJ online test via 288 ms

1 #Definition for singly-linked list.2 #class ListNode:3 #def __init__ (self, x):4 #self.val = x5 #Self.next = None6 7 classSolution:8     #@param head, a listnode9     #@return a ListNodeTen     defdeleteduplicates (Self, head): One         ifHead isNoneorHead.next isNone: A             returnHead -          -Dummyhead =listnode (0) theDummyhead.next =Head -          -p =Dummyhead -          whileP.next is  notNone andP.next.next is  notNone: +TMP =P -              whileTmp.next.val = =Tmp.next.next.val: +TMP =Tmp.next A                 ifTmp.next.next isNone: at                      Break -             ifTMP = =P: -p =P.next -             Else: -                 ifTmp.next.next is  notNone: -P.next =Tmp.next.next in                 Else: -P.next =Tmp.next.next to                      Break +         returnDummyhead.next

Ideas :

Set up the virtual table header Hummyhead to handle the linked list in a convenient way

P.next always points to the element to compare

A while loop is then nested in a while loop, skipping over the repeating elements.

If a repeating element is encountered: P does not move, p.next changes; If duplicate elements are not encountered, P=p.next

Tips: It is best to add a logical judgment pointer before using the pointer is not empty

Leetcode "Remove duplicates from Sorted List II" Python implementation