数据结构题典015：部分循环链表的逆转（ANSI C）

void inverse_part_llist( link_list lst, int i )
{
int j = 0;
node_ptr p = lst, s = NULL, q = NULL, r = NULL;
while( j < i - 1 && p != NULL )
{
++j; p = p->next;
}
s = q = p->next;
while( q != NULL )
{
r = q->next;
q->next = p->next;
p->next = q;
q = r;
}
s->next = p->next;
}