It's a really nice breakdown of sub-sequence calculation methods. If you're doing a letter-perfect diff calculation, or need to know how "different" two strings are, this is what you need. It even includes code and <i>explanations of the code</i> and how it all works.<p>All in all, the post is roughly worth a couple algorithm class sessions. Worth the read for just about anyone, if only for picking up a few new logical tricks.