83. Remove Duplicates from Sorted List

class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null) return head;
        ListNode node1 = head;
        ListNode node2 = head.next;
        while(node2 != null) {
            if(node2.val == node1.val) {
                node2 = node2.next;
            }else {
                node1.next = node2;
                node1 = node2;
                node2 = node2.next;
            }
        }
        node1.next = null;
        return head;
        
    }
}