Those are bad examples, but real interview questions tend to be "implement from scratch, live and without reference to any materials, these things you've forgot

Those are bad examples, but real interview questions tend to be "implement from scratch, live and without reference to any materials, these things you've forgotten about because you could take them for granted for such a long time". Also these days the trendy interview problem is longest common subsequence, which ends up testing "how recently did you review dynamic-programming techniques", not "can you code".