今天这道题是道简单题，使用双指针进行迭代即可，画了下草图如下

代码如下

class Solution {public ListNode reverseList(ListNode head) {if (head == null || head.next == null) {return head;}ListNode p = head, q = head.next, temp = null;while (q != null) {p.next = temp;temp = p;p = q;q = q.next;}p.next = temp;return p;}
}

题目链接：题单 - 力扣（LeetCode）全球极客挚爱的技术成长平台