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.

 

tag ： dummy node + tmp 

 

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode deleteDuplicates(ListNode head) {        if(head == null || head.next == null) {            return head;        }        ListNode dummy = new ListNode(0);        dummy.next = head;        head = dummy;                while(head.next != null && head.next.next != null) {            if(head.next.val == head.next.next.val) {                int tmp = head.next.val;                while(head.next != null && (head.next.val == tmp)) {                    head.next = head.next.next;                }            } else {                head = head.next;            }        }        return dummy.next;        }}