code: @Override
    public boolean add(int i)
    {
      int wordIndex = wordIndex(i);
      expandTo(wordIndex);
      int before = words[wordIndex];
      words[wordIndex] |= (1 << i);
      if (before != words[wordIndex]) {
        if (size >= 0) {
          size++;
        }
        return true;
      }
      return false;
    }
docs: {@inheritDoc}