They do seem awful interested in whether I can find all matching subtrees in a binary tree, though. Which, now that I think about, is the one thing I learned in college but haven't done even once on the job once in 20 years (I have had to find minimum cost paths in a tree, though. I couldn't have done it on the spot at the whiteboard, but my data structures and algorithms class was helpful in researching and figuring it out years later).