题解 | 删除有序链表中重复的元素-I

import java.util.*;


public class Solution {

    public ListNode deleteDuplicates (ListNode head) {
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        ListNode pre = dummy;
        while (head != null) {
            if (pre.val == head.val) {
                //如果相同，pre停下，删除head，head走一步再判断
                pre.next = head.next;
                head = head.next;
            } else {
                //如果不同，双个指针都走
                pre = pre.next;
                head = head.next;
            }
        }
        return dummy.next;
    }
}