[VirusNewbie]

is that not what they basically say? Most large companies will tell you to read a an algorithms book and give hints as to what questions they ask.

[daenz]

Some do. Other companies expect you to derive the algorithm from scratch if you haven't seen that one. If you don't know the algorithm, then question is over. It's unreasonable to expect someone to derive in 10 minutes something that took years to invent.