// @Title: 删除排序链表中的重复元素 (Remove Duplicates from Sorted List)
// @Author: qisiii
// @Date: 2020-06-01 19:07:13
// @Runtime: 1 ms
// @Memory: 38.2 MB
// @comment: 
// @flag: 
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {

        ListNode anext=head;
           while(anext!=null&&anext.next!=null){
               if(anext.val==anext.next.val){
                   anext.next=anext.next.next;
                   continue;
               }
               anext=anext.next;
           }
           return head;
    }
}

// @Title: 删除排序链表中的重复元素 (Remove Duplicates from Sorted List)
// @Author: qisiii
// @Date: 2024-01-14 16:23:05
// @Runtime: 0 ms
// @Memory: 43.3 MB
// @comment: 两个指针指向前后节点，后指针每轮移动，前指针只有一定不一样了才移动
// @flag: WHITE
/**
 * 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 head;
        }
        ListNode pre=head;
        ListNode now=head.next;
        while(now!=null){
            if(pre.val==now.val){
                pre.next=now.next;
            }else{
                pre=now;
            }
            now=now.next;
        }
        return head;
    }
}