public void afegirElement(String dia, int hora, Element e) {
        int i;
        if (dia.equals("dilluns")) i = 0;
        else if (dia.equals("dimarts")) i = 1;
        else if (dia.equals("dimecres")) i = 2;
        else if (dia.equals("dijous")) i = 3;
        else if (dia.equals("divendres")) i = 4;
        else if (dia.equals("dissabte")) i = 5;
        else i = 6;
        quadricula[i][hora].afegirElement(e);
    }