1、通过数组元素值，构造一个单向链表；

2、将链表元素以数组的形式打印出来，如“[1, 2, 3, 4]”

package listnodes;//创建节点类
class ListNode {int val;ListNode next;ListNode() {}ListNode(int val) { this.val = val; }ListNode(int val, ListNode next) { this.val = val; this.next = next; }
}public class RemoveElements {public static void main(String[] args) {//构造链表int[] nums = new int[]{1,2,2,1};ListNode head = null;//按照从后往前的顺序遍历数组，最终构造出一个链表for (int i = nums.length - 1; i >= 0; i--) {ListNode node = new ListNode(nums[i]);if(head != null){node.next = head;}head = node;}//处理链表Solution sol = new Solution();ListNode resNode = sol.removeElements(head, 2);//遍历链表并打印StringBuilder sb = new StringBuilder("[");while(resNode != null){if(sb.length() != 1) sb.append(", ");sb.append(resNode.val);resNode = resNode.next;}sb.append("]");System.out.println(sb);//[1, 1]}
}class Solution {public ListNode removeElements(ListNode head, int val) {if (head == null) {return head;}head.next = removeElements(head.next, val);return head.val == val ? head.next : head;}
}