As other mentioned algorithms I found that ideas behind Bloom filter (https://en.wikipedia.org/wiki/Bloom_filter https://en.wikipedia.org/wiki/Bloom_filter) and

As other mentioned algorithms I found that ideas behind Bloom filter (https://en.wikipedia.org/wiki/Bloom_filter https://en.wikipedia.org/wiki/Bloom_filter) and Geohash (not to be confused with geohashing or geo caching, see https://en.wikipedia.org/wiki/Geohash https://en.wikipedia.org/wiki/Geohash and Z-order curves) are extremely elegant and inspiring.