https://ethanzyf.com/tags/hashing/Recent content in Hashing on Ethan-ZYFHugoen-usSun, 31 May 2026 01:10:00 -0700https://ethanzyf.com/blog/hyperloglog/Sun, 31 May 2026 01:10:00 -0700https://ethanzyf.com/blog/hyperloglog/<p>HyperLogLog (HLL) is a probabilistic <strong>cardinality estimation</strong> algorithm: using a tiny, fixed amount of memory (typically ~12 KB), it estimates the number of <em>distinct</em> elements in a huge set, with a standard error of about 0.81%.</p>https://ethanzyf.com/blog/cuckoo-filter/Sun, 31 May 2026 00:45:00 -0700https://ethanzyf.com/blog/cuckoo-filter/<p>A Cuckoo Filter is a probabilistic data structure for approximate set membership. Like a Bloom filter it answers &ldquo;is this element <em>possibly</em> in the set?&rdquo; with a tunable false-positive rate and zero false negatives — but unlike a standard Bloom filter it also supports <strong>deleting</strong> elements, is more space-efficient at low false-positive rates, and is more cache-friendly on lookups.</p>