public static List<Integer> rotLeft(List<Integer> a, int d) {     
        List<Integer> rotations = new ArrayList<>();
        // Elements from index d to the end
        rotations.addAll(a.subList(d, a.size())); 
        // Elements from the start to index d
        rotations.addAll(a.subList(0, d)); 
        
        return rotations;
    }