void esercizio4(struct arrayList *ptr, int *ret)
{
    ret = 0;
    while (ptr->next != NULL)
    {
        int max = ptr->y;
        if (ptr->next->y < max)
            ptr->next = ptr->next->next;
        if (ptr->next->x < max)
            ptr->next->x = max;
        ptr = ptr->next;
        (*ret)++;
    }
    (*ret)++;
}