public void merge(Integer []lewe, Integer []prawe) // scalanie
    {
        int i = 0, j = 0, k = 0;
        while(k < tab.length && i < lewe.length && j < prawe.length)
        {
            if(lewe[i] < prawe[j] ) tab[k++] = lewe[i++];
            else tab[k++] = prawe[j++];
        }

        while(i < lewe.length)  tab[k++] = lewe[i++];
        while(j < prawe.length) tab[k++] = prawe[j++];
    }