public static int maxMin(int k, List<Integer> arr) {
    // Write your code here
        arr.sort(Comparator.naturalOrder());
        int result = Integer.MAX_VALUE;
        for (int i = 0; i <= arr.size() - k; i++) {
            result = Math.min(result, arr.get(i + k - 1) - arr.get(i)); 
        }
        return result;
    }