python/C over bunch of harder/less hard things. One was to always keep 10 smallest numbers out of a running stream, the most interesting one was how to find longest scrabble word given bunch letters & a dictionary (others I forgot, fairly simple stuff). There was a C question with adapting a lousy API to a better one with a hidden trick (usual 'how quickly can you optimize' stuff). Bunch of things about 'how you design memcached or search over all facebook posts' which is really system design (that was asked by mostly young guys that couldn't have possibly have had the real experience to judge why the hard, non-obvious trade-offs are needed vs. cool ideas but they were bright so the whiteboard shoot-out was fun).
