docs: public static int cardinalityInBitmapRange(long[] bitmap, int start, int end) {
      if (start >= end) {
        return 0;
      }
      int firstword = start / 64;
      int endword = (end - 1) / 64;
      if (firstword == endword) {
        return Long.bitCount(bitmap[firstword] & ( (~0L << start) & (~0L >>> -end) ));
      }
      int answer = Long.bitCount(bitmap[firstword] & (~0L << start));
      for (int i = firstword + 1; i < endword; i++) {
        answer += Long.bitCount(bitmap[i]);
      }
      answer += Long.bitCount(bitmap[endword] & (~0L >>> -end));
      return answer;
    }