public static int maxMin(int k, List<Integer> arr) {
        int currentUnfairness = 0;
        int minUnfairness = Integer.MAX_VALUE;
        
        List <Integer> sortedArr = arr.stream().sorted().collect(Collectors.toList());
        
        for (int i = 0, j = k - 1; j < sortedArr.size(); i++, j++) {
            currentUnfairness = sortedArr.get(j) - sortedArr.get(i);
            minUnfairness = Math.min(minUnfairness, currentUnfairness);
        }
        
        return minUnfairness;
    }