java删除单链表中的重复节点

package offer;
/*
* 1、删除单链表中的重复节点
* 输入 ： 2, 3, 3, 5, 7, 8, 8, 8, 9, 9, 10
* 输出 ： 2 5 7 10
*
* 2、单链表中重复节点只保留一个
* 输入 ： 2, 3, 3, 5, 7, 8, 8, 8, 9, 9, 10
* 输出 ： 2 3 5 7 8 9 10
*
*
*/
public class DeleteReNode {

//删除单链表中的重复节点public static ListNode deleteDuplication(ListNode pHead){    if(pHead==null)        return pHead;    ListNode first = new ListNode(0);    first.next = pHead;    ListNode p = pHead;    ListNode pre = first;    while (p != null && p.next != null){        if(p.val == p.next.val) {           int val = p.val;            //只需把下面的while改为注释的while，即可由情形1得到2           /*             while(p.next != null && p.next.val == val) {                p.next = p.next.next;            }            */            while(p != null && p.val == val) {                p = p.next;            }            pre.next = p;        }else {            pre= p;            p = p.next;        }    }    while(first.next != null) {        System.out.print(first.next.val + " ");        first = first.next;    }    return first.next;}public static void main(String[] args) {    //-构造单链表start----    int[] num = { 2, 3, 3, 5, 7, 8, 8, 8, 9, 9, 10 };     ListNode head = new ListNode(num[0]);    ListNode pre = head;    for (int i = 1; i < num.length; i++) {        ListNode node = new ListNode(num[i]);        pre.next = node;        pre = node;    }    //-构造单链表end-----    deleteDuplication(head);}

}

class ListNode {
int val;
ListNode next = null;
ListNode(int val) {
this.val = val;
}
}