public static List<Integer> icecreamParlor(int m, List<Integer> arr) {
        for (int i = 0; i < arr.size() - 1; i++) {
            List<Integer> sList = arr.subList(i + 1, arr.size());
            int complementLoc = sList.lastIndexOf(m - arr.get(i));
            if (complementLoc >= 0) {
                return List.of(i + 1, complementLoc + i + 2);
            }
        }
        return new ArrayList<>();
    }