It's not a waste of time (at least, I don't think it is). Personally, I think it's interesting that diff is based on LCS, and there are probably a lot of people who don't know that/might think it's interesting, too.

Maybe this is more of a meditation, but I don't really consider it to be horribly obnoxious to ask a question that might be answerable via documentation search. Espescially when you consider how frequently people post ludicrously simple questions like "how do I write a regexp that does this: ...?" The other monks don't jump on those folks' cases, with "perldoc perlre... RTFM!" I don't understand why some of them are upset when someone asks a far more intelligent and informed question that might be answered by doc-diving.

The truth of the matter is that doc-diving is often very difficult for finding where to start. You tend to run into the all-to-frequent problem of "I can find out what $module does, but I can't find which module does $thing".

Anyway, don't appologize, it was a perfectly reasonable question. I (and the other folks) were just pointing you towards resources that might help in your search for more info.