void merge(int tab[], int p, int q, int r)
{
    //int q = (p + r) / 2;
    int* tleft = (int*) malloc((q - p + 2)*sizeof(int));
    int* tright = (int*) malloc((r - q + 1)*sizeof(int));
    for (int i = 0; i < q - p + 1; i++)
    {
        tleft[i] = tab[p + i];
    }
    tleft[q - p + 1] = 1000;
    for (int i = 0; i < r - q; i++)
    {
        tright[i] = tab[q + i + 1];
    }
    tright[r - q] = 1000;

    int ri = 0; int le = 0;
    for (int i = p; i <= r; i++)
    {
        if (tright[ri] < tleft[le])
        {
            tab[i] = tright[ri];
            ri++;
        }
        else
        {
            tab[i] = tleft[le];
            le++;
        }
    }
    return;
}