code删除排序链表中的重复元素

美团校招一面

原题链接:
https://leetcode.cn/problems/remove-duplicates-from-sorted-list/description/

/**
 * 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) {
        if (head == null){
            return null;
        }
        ListNode dummy = new ListNode();
        dummy.next = head;
        ListNode cur = dummy.next;
        while (cur.next != null){
            if (cur.val == cur.next.val){
                // 这样不会死循环 因为每次都删除了一个元素
                // 所以cur不需要后移动一位 
                cur.next = cur.next.next;
            }else{
                cur = cur.next;
            }
        }
        
        return dummy.next;
    }
}