@Override
        public void insertToBand(int band, int[] hashes, int id) {
            String hexkey = toHex(band, hashes);
            RoaringBitmap idsBitmap = maps.get(hexkey);
            if (idsBitmap == null) {
                idsBitmap = RoaringBitmap.bitmapOf(id);
                maps.put(hexkey, idsBitmap);
            } else {
                idsBitmap.add(id);
            }
        }
Finds the number of bands that need to be used for a given similarity threshold.

@param nHashes
@param jaccardThreshold
@return
ache/src/main/java/achecrawler/minhash/LSH.java