Some months ago, I wrote a Python implementation of Daniel Lemire‘s Weighted Slope One collaborative filtering algorithm. Steve Jenson sent me a pointer to his Scala implementation last week, but his code is a straight port of the Python version,…

A few days ago, I wrote a Haskell library for building and working with suffix trees. It builds a suffix tree lazily, so even though its performance is O(n log n) on large input strings, it often has linear performance…