删除链表中的指定元素。

 

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode removeElements(ListNode head, int val) {        if(head == null)return null;        ListNode p,q;        p = head.next;        q = head;                while(p!=null) {            if(p.val == val) {                q.next = p.next;                p = p.next;            }            else {                p = p.next;                q = q.next;            }        }        if(head.val == val) {            head = head.next;        }                return head;    }}