图解反转单向链表

矫情吗；* 2022-01-16 02:53 203阅读 0赞

核心代码

> /\*\*  
>  \* Definition for singly-linked list.  
>  \* struct ListNode \{  
>  \*     int val;  
>  \*     struct ListNode \*pNext;  
>  \* \};  
>  \*/
> 
> /\* 反转函数，输入待反转链表头，返回反转后的链表头 \*/  
> struct ListNode\* reverseList(struct ListNode\* head)\{  
>     struct ListNode \*pre = NULL;  
>     struct ListNode \*next = NULL;  
>     while (head) \{  
>         next = head->pNext;  
>         head->pNext= pre;  
>         pre = head;  
>         head = next;  
>     \}  
>     return pre;  
> \}

1，存在链表：

![2019061423344593.png][]

2，定义两个辅助指针

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70][]

3，进入第1次while循环（反转第1个节点）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 2][]

4，进入第2次while循环（反转第2个节点）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 4][]

5，进入第3次while循环（反转第3节点）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 5][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 6][]

6，进入第4次while循环（反转第4节点，结束）

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 7][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 8][]

[2019061423344593.png]: /images/20220114/861daafbfff541ddab21c558286d723f.png
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RhaXl1ZG9uZzIwMjA_size_16_color_FFFFFF_t_70 1]: /images/20220114/10493fd03290472faf94a267352704b0.png
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