The most surprising Unix programs
« Typo was as surprising inside as it was outside. Its similarity measure was based on trigram frequencies, which it counted in a 26x26x26 array. The small memory, which had barely room enough for 1-byte counters, spurred a scheme for squeezing large numbers into small counters. To avoid overflow, counters were updated probabilistically to maintain an estimate of the logarithm of the count. »<p>This sounds like something from the same family as hyperloglog<p>Wikipedia traces that back to the Flajolet–Martin algorithm in 1984. When would typo have been written?