נתונות ארבע פעולות:

public static double one(int num)
{
    return two(num, 0, 0);
}

private static double two(int num, int s, int c)
{
    if (num == 0) return (double)s / c;
    return two(num / 10, s + (num % 10), c + 1);
}

public static int[] three(int[] arr, int p)
{
    int n = arr.length;
    int[] temp = new int[n];
    four(arr, temp, 0, 0, n - 1, p);
    return temp;
}

private static void four(int[] arr, int[] temp, int k, int left, int right, int p)
{
    if (k < arr.length)
    {
        if (one(arr[k]) > one(arr[p]))
        {
            temp[right] = arr[k];
            four(arr, temp, k + 1, left, right - 1, p);
        }
        else
        {
            temp[left] = arr[k];
            four(arr, temp, k + 1, left + 1, right, p);
        }
    }
}