I had an interview about a decade ago, before doing a massive amount of prep on toy problems became standard for interviews candidates. The first question was

I had an interview about a decade ago, before doing a massive amount of prep on toy problems became standard for interviews candidates. The first question was to implement itoa, by far the easiest question of the day, and one presumably designed to warm the candidate up while also directing interviewers whether they should even bother with their harder questions. I walked to the whiteboard and just wrote the implementation top to bottom without mistakes, then explained the code. I may have been a little lucky that I didn’t have any missteps, such as briefly forgetting to handle negatives or zero, or not immediately realizing that the first idea that pops into your head for pulling digits off will be a little awkward as you want to fill the string in the reverse order. But I’d never done itoa before so I didn’t think to offer any sort of disclaimer about why this was particularly easy, I was just happy with my performance and ready to do the next question. The interviewers excused themselves and I saw them consulting the person who recommended me down the hall. I was surprised to learn that they were asking if it was possible I’d been supplied a list of interview questions and memorized the answers, to work out whether they even wanted to proceed from there.