leetcode-top面试题反转链表

我会带着你远行 2021-11-27 07:10 233阅读 0赞

**题目**  
反转一个单链表。  
示例:  
输入: 1->2->3->4->5->NULL  
输出: 5->4->3->2->1->NULL  
**思路**  
方法一：迭代  
![在这里插入图片描述][20190724144836695.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]

public ListNode reverseList(ListNode head) {
        ListNode prev = null;
        ListNode curr = head;
        while (curr != null) {
            ListNode nextTemp = curr.next;
            curr.next = prev;
            prev = curr;
            curr = nextTemp;
        }
        return prev;
    }

![在这里插入图片描述][20190724144911937.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 1]

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

![在这里插入图片描述][20190724145006241.png]  
作者：LeetCode  
链接：[https://leetcode-cn.com/problems/two-sum/solution/fan-zhuan-lian-biao-by-leetcode/][https_leetcode-cn.com_problems_two-sum_solution_fan-zhuan-lian-biao-by-leetcode]  
来源：力扣（LeetCode）  
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

[20190724144836695.png]: /images/20211126/aa3707713722460999bf085a2467efb7.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]: /images/20211126/6c36ca7293804d2c9382444914564bcb.png
[20190724144911937.png]: /images/20211126/6780588dabc847578fd82648c0824f5d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 1]: /images/20211126/d807c89eb98f4b24868aa83824ea7762.png
[20190724145006241.png]: /images/20211126/34bf6ee3f982441eb8836213ccd8f01d.png
[https_leetcode-cn.com_problems_two-sum_solution_fan-zhuan-lian-biao-by-leetcode]: https://leetcode-cn.com/problems/two-sum/solution/fan-zhuan-lian-biao-by-leetcode/