void Xarxa::ordenar_vector(vector<Tren>& v) {
    int i, j;
    i = 0;
    while (i < v.size()) {
        j = 0;
        while (j < v.size()) {
            if (v[i].consultar_arribada() < v[j].consultar_arribada()) {
                Tren aux = v[i];
                v[i] = v[j];
                v[j] = aux;
            }
            else if (v[i].consultar_arribada() == v[j].consultar_arribada() and v[i].consultar_id() < v[j].consultar_id()) {
                Tren aux = v[i];
                v[i] = v[j];
                v[j] = aux;
            }
            ++j;
        }
        ++i;
    }
}