Comment by cletus | Hacker News Reader

Comment by cletus | Hacker News Reader

Bizarre.

Yes, Googling an answer to a Google interview question from SO is in fact verboten. A seasoned interview can normally pick that up anyway. But a note to potential Google interviewees: if you're caught doing this it will pretty much disqualify your application. We're interested in how you think and how you solve problems, not what you can pass off as knowing.

Interestingly, he mentions the NDA and then goes on to broadly describe the question anyway. If all this is true, I'm not a fan of bit-twiddling questions. It's something you either know or you don't (like reversing bits in O(log n)). This is meant to be an interview not a trivia quiz. I get mad every time I see those kinds of questions asked.

Anyway, another note: if it's on your CV, it's fair game to be asked about. So if you put that you wrote a low of embedded C/C++ in such a way that you'd be expected to do a lot of bit-twiddling then yes, bit-twiddling is absolutely fair game (IMHO).

If however you put that you've only done Python/Django, Clojure and Scala then it's a stupid question to ask (IMHO).

The second phone interview if accurate disappoints me as well. Perhaps this was a product of the position you applied for or what you put on your CV?

As far as intern matching goes, yes there is absolutely room for improvement there.

Note to other commenters: PLEASE PLEASE PLEASE stop spreading this nonsense that Google asks engineering interviewees stupid questions like "a man drove his car to a hotel and lost his fortune, what happened?" This is NOT what we do. The sooner people stop spreading this misinformation the better.

I've interviewed with Google twice, and both times I was so unhappy with the experiences I declined the offers. Many friends work at Google and are happy, so this seems like an instance of getting unlucky with the loops... but don't dismiss off the cuff.

The very first question I got in fall 2010 on a phone interview was "How many ping pong balls fit within a school bus?" The second question was "When would you use a virtual destructor in C++?" without C++ being on resume or confirming if I had any experience with it. I used C++ many years ago and could reason through, but I did walk away thinking how unfair the interviewer was. There were other small instances that led me to say no.

Then in fall 2011 at the Googleplex, my first question was "I'm XYZ and I worked on Google+. That's all you need to know about me. Why am I interviewing you?" It was pretty condescending, and if that was based on my resume then shame on me. If this had been at a bar I would have responded more colorfully, but during an interview all you can do is be polite and answer the question.

While I fully believe most of Google tries to be fair and reasonable during interviews, I've had two experiences where individuals were not. YMMV.

P.S. The bit-wise question sounds like the interviewer asking why UTF-8 is preferred over UTF-16 or something and how you would detect which encoding was used. Regardless of what language you know you should be able to answer this as it affects everyone on the web. At least, that's going to be my new question for interviewing people :)

I find questions like the ping pong ball question rather trying, but I guess there's a long precedent for it. My understanding is that you're supposed to do a back-of-the-envelope calculation that gets you within an order of magnitude or so of the correct answer.

One problem with questions like this is that unless you know that you're supposed to just do a back-of-the-envelope calculation, they can leave you completely flabbergasted, as the questions sound as if they are asking for an accurate answer, which you'd have no reasonable way of determining.

Also, for me, asking me to do any math at all while someone is staring over my shoulder, or what have you, is going to cause me to make mistakes like sqrt(36) == 9, and I have a degree from MIT. Consequently, I hate this style of interview with a passion.

Regarding your experience with the condescending interviewer: I had a similar experience in my last job-interviewing round, and got really pissed, but tried to stay polite and answer the question. This doesn't work though: I spent the whole time distracted, with my mind considering the paradox of a founder having such behavior, and that I'd be using the guy as a mentor. The result: I underperformed on the problem, and got walked out, leaving me feeling like the fool. My new rule (and this goes for general life too): I call people's bad behavior, but not in a judgmental way, but rather to avoid adding a negative dynamic as a kernel to the relationsihp (e.g., in a meeting, I speak up if someone could interpret something poorly, to clarify it, because otherwise some subset of the people will be passive agressive and fume and suffer a downward spiral, rather than speak up themselves). I would have felt so much better about myself if, during that interview, I had said, "You know, this isn't going to work; there is no point spending your time on me anymore." And then walked out.

Then in fall 2011 at the Googleplex, my first question was "I'm XYZ and I worked on Google+. That's all you need to know about me. Why am I interviewing you?"

Out of curiosity, did the interviewer ever explain this odd introduction, or what he/she was trying to get at?

I've been asked bit twiddling in O(log n) questions before and it was in no way supposed to be a test of my knowledge. It was a way for the interviewer to evaluate my ability to not know how to answer a question. It took me almost an hour to solve, but it gave the interviewer a pretty clear insight into my ability to approach something new.

In my experience the best interview questions I've had have been situations where I was asked a question about something I was not familiar with. The interviewer then gave me a 5 minute overview of the things I need to know (like which synchronization methods are available in pthreads, for instance) and then give me the chance to apply the things I just learned. I think most employers care far more about how quickly you can pick up new things than they care about what you already know, and it left me with the feeling that they gave me an offer because of what I can do, rather than what I already know.

Some bit-twiddling questions are a fair game to ask even for folks who haven't done low-level C and C++. Asking esoterica from Hacker's Delight (an excellent book, by the way, but in no way a source of interview questions), is not, but I doubt Google does this.

Bitwise operators are just as available in Java. I've done bit-twiddling in production Java code, it's something you need to do if you ever, e.g., work on a serialization library.

Understand, words, bits, bytes, and bitwise operators (big part of How Computers Work (TM)(R)) is something worth knowing (and not just to pass an interview).

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