People talking about how he "hacked the interview process" are missing the point: as a hiring manager I'd gladly hire this guy even knowing that so much of what he did was not entire genuine. He took a problem (I need a job), implemented a solution (applied and interviewed at a TON of places in that short of a timeframe), and successfully iterated on that solution until he had completely mastered it! In a very short time period he went from being unable to solve a variety of programming problems (or doing so poorly) to internalizing the how & why of the optimal solutions - this is what good software development is about!
I care a lot more about initiative and problem-solving skills than I do reversing linked-lists - this guy has the former two in spades.
Sure, if you're looking for someone who is hard working and willing to learn, then this type of candidate is perfect for you.
But if you're screening for candidates with development experience who you can rely on for technical knowledge, the idea that someone can game your interview process in less than two weeks without previous knowledge is horrifying. But I'm guessing that people looking to hire experienced candidates aren't basing hiring decisions on questions about reversing linked-lists.
I care a lot more about initiative and problem-solving skills than I do reversing linked-lists - this guy has the former two in spades.