@Override
    public boolean retainAll(Collection<?> c) {
        int n = this.size();
        for(LinkedList<E> bucket : buckets) {
            for(E e : bucket) {
                if(!(c.contains(e))) {
                    this.remove(e);
                }
            }
        }
        if(n != this.size())
            return true;
        return false;
    }