[InclinedPlane]

There are two kinds of questions worth asking in a coding interview, in my opinion. Very straightforward questions that should be solved by anyone with familiarity with the relevant techniques (basic programming, bit-wise operations, multi-threading, depending on the level you want to hit) basically as fast as they can write. And open ended questions which require a lot of back and forth dialogue and design and give you a chance to gauge the experience and overall maturity of the candidate. These are depth / basic competence versus breadth questions. You simply can't expect to get a much better read than that in an hour, even working side by side with someone for a year you won't necessarily have a good sense of how good a dev they really are, you're not going to find that out in an hour or a day for sure. The best you can hope for is to gauge basic competence and make a guess at sophistication and maturity then hope for the best.