void sa(linked_list_t **head)
{
    char *temp = (*head)->value;
    (*head)->value = (*head)->next->value;
    (*head)->next->value = temp;
    return;
}

void ra(linked_list_t **head)
{
    if (!*head || !(*head)->next) {
        return;
    }
    linked_list_t **pp = &(*head)->next;
    while (*pp && (*pp)->next)
        pp = &(*pp)->next;
    linked_list_t *tmp = *head;
    *head = *pp;
    *pp = tmp;
    (*head)->next = (*pp)->next;
    (*pp)->next = NULL;
    return;
}

void pa(linked_list_t *head, linked_list_t *head2)
{
    while (head->next != NULL) {
        head = head->next;
    }
    char *tmp = head->value;
    if (!head2 || !head2->next) {
        push_list(&head2, node_create(tmp));
        return;
    }
    while (head2->next != NULL) {
        head2 = head2->next;
    }
    push_list(&head2, node_create(tmp));
}