删除链表中重复的结点

/*
 public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    public ListNode deleteDuplication(ListNode pHead)
    {
        ListNode first = new ListNode(-1);
        first.next = pHead;
        ListNode p = pHead;
        ListNode last = first;
        while(p != null && p.next != null) {
            if(p.val == p.next.val) {
                int val = p.val;
                while(p != null && p.val == val) {
                    p = p.next;
                }
                last.next = p;
            }else{
                last = p;
                p = p.next;
            }
        }
        return first.next;
    }
}