Clever title. In my experience, in a practical sense, tries tend to be very memory intensive with only a marginal increase in speed over other alternatives like simple hash lookups. However, this is a very interesting and more typical use-case for a trie. I've always like it better than using Hamming distance which still seems to get recommended in undergraduate texts.<p>Oh, and I glossed over the perl code, until I reread it and realized it was sleep code. First time hearing about this language...interesting.<p><a href="http://sleep.dashnine.org/" rel="nofollow">http://sleep.dashnine.org/</a>