LeetCode: Remove Duplicates from Sorted List

Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if(head==null) return head;
        
        ListNode n1= head;
        while(n1.next!=null){
            if(n1.next.val==n1.val){
                n1.next=n1.next.next;
            }else{
                n1=n1.next;   
            }
        }
        return head;
    }
}