ding.java

class Ding
{
    public static int[][] splitInBuckets(int min, int max, int nBuckets, int[] arr) throws Exception
    {
        if (min < 0)
        {
            throw new Exception("min cannot be smaller than 0");
        }
        int[][] output      = new int[nBuckets][]; // the output array
        int[] distribution  = new int[nBuckets];   // stores the distribution of elements in the array
        int[] found         = new int[nBuckets];   // stores how many digits of each group are found
        int useMin          = min == 0 ? 1 : min;  // if min is 0, use 1 to calculate min for each slice

        // Calculate the distribution
        for (int i = 0; i < arr.length; i++)
        {

            for (int j = 0; j < nBuckets; j++)
            {
                // if the value in the range of this slice, add 1 to the length of the slice and break
                if (
                        (arr[i] >= (j*useMin)) && (arr[i] <= (int) Math.ceil(max/nBuckets))
                )
                {
                    distribution[j]++;
                    break;
                }
            }
        }

        // initialize all output sub arrays
        for (int i = 0; i < nBuckets; i++)
        {
            output[i] = new int[distribution[i]];
        }

        // fill up the output
        for (int i = 0; i < arr.length; i++)
        {

            for (int j = 0; j < nBuckets; j++)
            {
                if (
                        (arr[i] >= (j * (j*useMin)-1)) && // min is the bucket no. x min
                        (arr[i] <= (j+1)*(int) Math.ceil(max/nBuckets)) // max is bucket no. * max divided by noBuckets. +1 bc j starts at 0
                )
                {
                    output[j][found[j]] = arr[i];
                    found[j]++;
                    break;
                }
            }
        }

        return output;
    }
}