&gt; If you hire using know it or not questions about binary trees<p>The article author doesn&#x27;t think of his question as a &quot;know it or not&quot; question, but a &quot;you should be able to figure this out&quot; question:<p>&gt; Here&#x27;s the first reason why this question is so good: a skilled programmer can map their intuition to code. You can tell at a glance whether a binary tree is symmetric, but beginners will often struggle with a question like this because they approach this problem from a visual&#x2F;intuitive angle rather than the logical angle.<p>I think it&#x27;s a fair criticism to say that, at this point, &quot;reverse a binary tree&quot; is something a lot of applicants will have simply memorized rather than figuring out on the fly. But (to play Devil&#x27;s Advocate) isn&#x27;t the <i>goal</i> of the question - to test a candidate&#x27;s ability to think logically and problem-solve on the fly - a reasonable one?<p>It seems to me the real problems with whiteboard-coding interviews aren&#x27;t that what they&#x27;re trying to test - problem-solving on the fly - isn&#x27;t useful or valuable, but that whiteboard coding is confounded by so many irrelevant variables: ability to think under pressure, ability to code &quot;in your head&quot; (without an editor, IDE or REPL), memorizing solutions, and so forth.