Leetcode82. 删除排序链表中的重复元素 II

82. 删除排序链表中的重复元素 II

Difficulty: 中等

给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 _没有重复出现 _的数字。

示例 1:

输入: 1->2->3->3->4->4->5
输出: 1->2->5

示例 2:

输入: 1->1->1->2->3
输出: 2->3

Solution

Language: java

​/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode pre = null, p = head, newHead= null;
        while(p != null){
            if(p.next != null && p.next.val == p.val){
                if(pre != null) pre.next = null;
                while(p.next != null && p.next.val == p.val){
                    ListNode t = p;
                    p = p.next;
                    t.next = null;
                }
            }else{
                if(pre == null) newHead = p;
                else pre.next = p;
                pre = p;
            }
            p = p.next;
        }
        return newHead;
    }
}