docs: public static int select(long w, int j) {
      int part1 = (int) (w & 0xFFFFFFFF);
      int wfirsthalf = Integer.bitCount(part1);
      if (wfirsthalf > j) {
        return select(part1, j);
      } else {
        return select((int) (w >>> 32), j - wfirsthalf) + 32;
      }
    }