反转一个单链表

 

利用三个连续指针cur、fw1、fw2，从头(设定为slink)开始指向三个节点，然后进行反转操作，循环进行：

 

//最开始的状态
cur = slink;
fw1 = slink->next;
fw2 = fw1->next;
slink->next = NULL;

//反转一次
fw1->next = cur;
cur = fw1;
fw1 = fw2;
fw2 = fw2->next;

完整的代码请参考：

struct mynode{
    int data;
    struct mynode *next;
};

struct mynode *single_link_reverse(struct mynode *slink)
{
    struct mynode *cur;
    struct mynode *fw1;
    struct mynode *fw2;

    /* zero or one node*/
    if (NULL == slink || NULL == slink->next)
        return slink;

    cur = slink;
    fw1 = slink->next;
    fw2 = fw1->next;
    slink->next = NULL;

    /*two nodes*/
    if (NULL == fw2)
    {
        fw1->next = cur;
        return fw1;
    }

    /*three+ nodes*/
    while (NULL != fw2)
    {
        fw1->next = cur;
        cur = fw1;
        fw1 = fw2;
        fw2 = fw2->next;
    }

    /*now fw1 is the last node*/
    fw1->next = cur;
    return fw1;
}

sxg