I can't tell whether knowing it in advance makes no difference at all. If there was a substantial difference, I'd have expected these candidates to excel, and even finish the extended questions, but they did not. Were they perhaps really bad programmers that got lucky? No, I don't think so, since I can evaluate a lot about their coding style and how they talk.
What's the difference between having seen the question before, and getting a lucky thought that solves it within the first minute? I don't see any reason to treat these differently.
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