• 全部代码 

public class Num203 {
    public ListNode removeElements(ListNode head, int val) {
        ListNode dummyHead = new ListNode(-1);
        dummyHead.next = head;
        ListNode prev = dummyHead;
        while (prev.next != null){
            if (prev.next.val == val){
                //找到待删除节点
                prev.next = prev.next.next;
            }else {
                prev = prev.next;
            }
        }
        return dummyHead.next;
    }
}