Why would you expect grads to come up with the logarithmic solution? That's a piece of trivia that says absolutely nothing about their actual capabilities, just

Why would you expect grads to come up with the logarithmic solution? That's a piece of trivia that says absolutely nothing about their actual capabilities, just how well they remember their linear algebra. Also why stop there? An actual smart coder would have looked up the constant time solution instead of bothering with any of that.