LeetCode 82. Remove Duplicates from Sorted List II（删除链表中的重复节点）

原题网址：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

.
方法：直接处理，注意引入辅助头节点是个好办法。

/**
* 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) {
ListNode start = new ListNode(0);
start.next = head;
ListNode current = start;
while (current.next != null && current.next.next != null) {
if (current.next.val == current.next.next.val) {
ListNode duplicate = current.next.next.next;
while (duplicate != null && duplicate.val == current.next.val) {
duplicate = duplicate.next;
}
current.next = duplicate;
} else {
current = current.next;
}
}
return start.next;
}
}