Leetcode: Remove Duplicates from Sorted List II

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

Solution:

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode dummy = new ListNode(0);
        ListNode list = dummy;
        ListNode pointer= head;
        while(pointer != null )
        {
            if(pointer.next != null && pointer.val == pointer.next.val)
            {
                int value = pointer.val;
                while(pointer!=null && pointer.val == value)
                    pointer = pointer.next;
            }
            else
            {
                list.next = pointer;
                list = list.next;
                pointer = pointer.next;
            }
        }
        list.next = null;
        return dummy.next;
        
    }
}