Remove Duplicates from Sorted List

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

Example 1: Input: 1->1->2 Output: 1->2 Example 2: Input: 1->1->2->3->3 Output: 1->2->3

class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null) return null;
        ListNode dummy = head;
        while(head != null && head.next != null) {
            if(head.val == head.next.val) head.next = head.next.next;
            else head = head.next;
        }
        return dummy;       
    }
}