void shellsort (int[] a, int n)

{

    int i, j, k, h, v;

    int[] cols = {1391376, 463792, 198768, 86961, 33936, 13776, 4592,

                    1968, 861, 336, 112, 48, 21, 7, 3, 1}

    for (k=0; k<16; k++)

    {

        h=cols[k];

        for (i=h; i<n; i++)

        {

            v=a[i];

            j=i;

            while (j>=h && a[j-h]>v)

            {

                a[j]=a[j-h];

                j=j-h;

            }

            a[j]=v;

        }

    }

}