Counting sort

class Main
{
    public static void main (String[] args)
    {
        int arr[] = { 1,4,4,1,0,1 };
        int n = arr.length; int k=5;
        countSort(arr, n, k);

        for (int i = 0; i < n; i++)
            System.out.print( arr[i] + " ");

    }

    static void countSort(int arr[], int n, int k)
    {
        int[] count=new int[k];
        for(int i=0;i<k;i++)
            count[i]=0;
        for(int i=0;i<n;i++)
            count[arr[i]]++;

        for(int i=1;i<k;i++)
            count[i]=count[i-1]+count[i];

        int[] output=new int[n];
        for(int i=n-1;i>=0;i--){
            output[count[arr[i]]-1]=arr[i];
            count[arr[i]]--;
        }
        for(int i=0;i<n;i++)
            arr[i]=output[i];
    }
}