力扣（LeetCode）官网 - 全球极客挚爱的技术成长平台

带头结点

class Solution {
    ListNode reverseList(ListNode head) {
        ListNode dummy = new ListNode(-1);
        ListNode cur = head;
        while(cur != null) {
            ListNode next = cur.next;
            cur.next = dummy.next;
            dummy.next = cur;
            cur = next;
        }
        return dummy.next;
    } 
}

不带虚拟头结点

class Solution {
    public ListNode reverseList(ListNode head) {
        ListNode cur = head;
        ListNode pre = null;
        while(cur != null) {
            ListNode next = cur.next;
            cur.next = pre;
            pre = cur;
            cur = next;
        }
        return pre;
    }
}

拓展

通过递归来实现反转

class Solution {
    public ListNode reverseList(ListNode head) {
        if (head == null || head.next == null) {
            return head;
        }
        ListNode newHead = reverseList(head.next);
        head.next.next = head;
        head.next = null;
        return newHead;
    }
}