How to react when asked a question you already know during an interview

Question

The short story:- If you are asked a tough algorithmic/puzzle question during an interview, whose solution is already known to you, do you:-

1. Honestly tell the interviewer that you know this question already? -- this could result in bursting the interviewer's ego and him increasing the complexity level of the subsequent questions.
2. Do an Oscar deserving performance and act as if you are thinking and trying hard and slowly getting to the solution? -- depending on your acting skills, could majorly impress the interviewer making the rest of the interview easier.

Long story:- OK, this question comes as a result of what happened to me in a recent telephonic interview that I gave - the interview was supposed to be all algorithmic. The interviewer started with an algorithmic question which I had luckily already seen here on Stackoverflow. The best solution to that problem is not very intuitive and is more of a you-get-it-if-you-know-it kind. Now, just to not disappoint the interviewer too much, I took a few seconds as if I was pondering on the problem and then blurted out the answer which I knew too well having read and admired it on SO already. But I guess that gave it away to the interviewer that I already knew this question and since then, he started asking me for more efficient solutions and I kept coming up with approaches (even if not correct or more efficient, but I did touch a lot of different data structures and algos) and he kept asking for more efficient solutions and generally seemed put off by my initial salvo which was unexpected. What should I have done?

Cheers!

Answer 1

It depends on what the interviewer wants. If he just wants you to give "the right answers" to each question on his list - pretending will make sense. If he is going to dig deeper he will do it anyway and ask you more detailed questions so pretending you think hard makes no sense and just wastes time. You'll easily get which mode the interviewer is in from the very beginning.

From my experience of conducting interviews: I always try to dig as deep as possible to get an estimate of what really stands behind the "C/C++ - 5 years of experience". All the questions I ask are quite simple so imitating hard thinking will only waste time and drain energy. After all I can't afford an interview longer than say an hour - it's best interest of the interviewee to quickly demonstrate his real skills and knowledge.

Answer 2

If I were giving you an interview and I felt that you were being dishonest, I'd reject you. I don't want to work with someone who'll lie to get ahead.

Answer 3

I'd put it the other way round - it depends what you want! The interview is as much a chance for you to interview the company as it is the other way round and if your prospective employer is asking you to jump through obvious hoops then perhaps they're not going to be the most creative company on the planet. If you want to play along, answer the question, if you want to go for gold then ask him if he doesn't have something more challenging/interesting for you to think about.

I like questions along the lines of 'define me an interface description for this table' where everything is wide open, somehow obvious but somehow nonsensical (like change requests usually are ;-) ) and entirely for the candidate to interpret. It shows up more about the candidate's ability to think and function than going for the standard rubbish.

Answer 4

The point of these questions is more so see how you THINK about solving a problem rather than the actual solution.

Answer 5

If you know the answer, just give it. If the interviewer asks how you got it so fast, then be honest. Impress the interviewer with your intelligence, enthusiasm, and charm, not with your acting skills.

I wonder why you are worried that the interviewer might start asking tougher questions. If the interviewer only asks softball questions, then either the interviewer isn't very good, or doesn't think much of your abilities.

If an interviewer just asks a bunch of puzzle questions whose answers can be looked up on Google, then the interviewer is a moron. You don't want to work for that kind of person anyway.

Don't approach an interview as if it is a quiz or an interrogation. It should be a conversation to determine whether the position is a good one for you. If you fit, then there is nothing to worry about. If you don't fit, then it's probably a good thing to "fail".