Is anyone else seeing an error in sample test case 1? It expects a '0' as the last element of the result. This implies that the test case expects the algorithm to count one additional element beyond the largest element in the list.

input: 63 54 17 78 43 70 32 97 16 94 74 18 60 61 35 83 13 56 75 52 70 12 24 37 17 0 16 64 34 81 82 24 69 2 30 61 83 37 97 16 70 53 0 61 12 17 97 67 33 30 49 70 11 40 67 94 84 60 35 58 19 81 16 14 68 46 42 81 75 87 13 84 33 34 14 96 7 59 17 98 79 47 71 75 8 27 73 66 64 12 29 35 80 78 80 6 5 24 49 82

my result: 2 0 1 0 0 1 1 1 1 0 0 1 3 2 2 0 4 4 1 1 0 0 0 0 3 0 0 1 0 1 2 0 1 2 2 3 0 2 0 0 1 0 1 1 0 0 1 1 0 2 0 0 1 1 1 0 1 0 1 1 2 3 0 1 2 0 1 2 1 1 4 1 0 1 1 3 0 0 2 1 2 3 2 2 2 0 0 1 0 0 0 0 0 0 2 0 1 3 1

expected result: 2 0 1 0 0 1 1 1 1 0 0 1 3 2 2 0 4 4 1 1 0 0 0 0 3 0 0 1 0 1 2 0 1 2 2 3 0 2 0 0 1 0 1 1 0 0 1 1 0 2 0 0 1 1 1 0 1 0 1 1 2 3 0 1 2 0 1 2 1 1 4 1 0 1 1 3 0 0 2 1 2 3 2 2 2 0 0 1 0 0 0 0 0 0 2 0 1 3 1 0

javascript

function countingSort(arr) {
    let counterArray = Array(100).fill(0);
    
    for (let number of arr) {
        counterArray[number]++
    }
    return counterArray;
}

Python

def countingSort(arr):
    
    sol=[0]*100  # creates an array filled with 0s
    for a in arr : 
        sol[a] += 1

    return sol

C# code:

public static List<int> countingSort(List<int> arr)
    {
        int[] occurences = new int[100];
        foreach (var item in arr)
            occurences[item]++;

        return occurences.ToList();
    }

Easy Java solution:

public static List<Integer> countingSort(List<Integer> arr) {
    //creates list with 100 elements filled with zeros
    List<Integer> res = new ArrayList<Integer>(Collections.nCopies(100, 0));
    for(Integer a : arr)
            res.set(a, res.get(a)+1);
    return res;
}