Already Know the Interview Solution? Say Something

While some candidates don’t prepare at all for coding / algorithms interviews (eek!), others spend so much time preparing that they already know the answers to problems. “Score!” they think. “Now I’ve nailed the question.”

businessman scoresOh, how very, very misguided that is.

Let’s take a step back. Algorithm questions are designed to test your problem solving skills. When you’re asked, for example, to design an algorithm to find the longest palindrome in a string, your interviewer doesn’t care if you know the answer. Not one tiny bit.

Your interviewer is not testing knowledge, they’re trying to understand how good you are at solving problems you haven’t seen before. They want to understand your problem-solving skills.

If you just spit out the optimal solution to the problem, you’re not giving the interviewer a chance to see your approach. Great, you know the solution, but so what? The interviewer doesn’t care about that. And on top of that, many interviewers will see you as dishonest for not admitting that you know the problem.

Some candidates “wise up” to this and decide instead to pretend to be solving the problem from scratch. They’ll fake struggle for a bit before finding their way to the solution. This is also unwise as it comes with a host of problems:

  • You’re basically acting. Are you that good of an actor? Are you sure?
  • You’re really deceiving your interviewer. If you get caught, you might get rejected on those grounds alone.
  • You might have misheard the problem, or it might be a slightly different problem than you’d heard before. Your struggling could be making you look a lot worse than you are.
  • Your interviewer has probably seen dozens of candidates solve this exact question before. She knows exactly what a “normal” path is, and what good performance looks like. You, however, do not. You’ve previously solved it once, if that (you might have just read the solution before). You don’t know what “good performance” looks like – so how can you act like a good performer on this problem? You’ll likely get caught – or wind up struggling more than a good candidate would.
  • Even if you’re not caught on that problem, what have you really shown? Your interviewer will just go on to a new problem – one that you probably haven’t heard before – and then your weaker performance here will make your interviewer suspicious of your “strong” performance earlier.

“Fake struggling” ends up hurting your performance more than it helps you. Don’t bother.

On the other hand, if you tell your interviewer that you know the problem, he’ll just move on to a new question (or potentially ask you to solve it anyway). You’ll probably get some “bonus points” for your honesty too.

Also, it should be said: It’s just the right thing to do. Pretending to solve a question that you’ve heard before just isn’t particularly ethical. Don’t you want to do the right thing and the smart thing?

23 Responses to “Already Know the Interview Solution? Say Something”

  1. You missed what, to me, is the obvious problem with faking the solution: future failure.
    i.e. If they hire you then ask you to solve problems in “real life”, unless you’re really that good at solving problems, then you’ll fail over and over and will show your incompetence and possibly get fired.
    Of course, if you’re good at solving problems, maybe it’s okay to “fake” it through, but my experience is that most good problem-solvers are bad actors, which goes back to your first point.

      • Mack Michales

        ^Exactly. That’s why many interview processes are jokes anyway. Including the fact that many times, a friend or family member of someone who already works for the company is already lined up to get the position, so the real “faking” in the interview process is by the interviewers, wasting interviewees time. Let’s ALL lay our cards out on the table and see how many people still waste their time with various companies/interviewers once the truth about the situation is know.

  2. Beresford Davidson

    People who go out of their way to seek employment with any company and earn the respect for an interview should be treated with utmost respect and to some extent paid for their time and effort; we use to do that in New York City back in the day. Employers are not above the job seeker; they need their talent and skills. The potential employed or person seeking employment helps to prolong the life of the business and keep the business in the marketplace. In a stressful economy employers may appear at times to have the upper hand, but that’s not true, but their recruiters behave as such, which is pure arrogance that puts the employers’ business and reputation at risk. The last thing a person, seeking employment of their honed skills and talent need under their stress belt, is some s/he loon giving them some test for them to prove if they know how to think, through an algorithm test. That’s bull! Be done with that nonsense behavior! We are all adults with responsibilities beyond the workplace. The potential employee is the person who will make the business sing and dance profits and prolong the life of the business way into the future of its owners’ retirement. Human resource’s recruiters must stop stressing out the potential employees when they come knocking at the door to promote their skill set and talents. Treat these people with utmost respect; giving a test is insulting and demeaning. The recruiter can explain a problem their company is having and asks the potential employee how they would go about resolving those problems based on their years of work experience on such problems. Expect a timely response or no response and leave it at that. The recruiters should thereafter send a letter of thanks to the potential employee thanking him for stopping by to review the company’s request for their honed skills and talents. If the company knew how to solve their problems without the need for new employees they would not have advertised for help wanted.

    • “If the company knew how to solve their problems without the need for new employees they would not have advertised for help wanted.”
      While that is very true, ultimately, the company wants to pick the best candidate. Since it seems that very few people know how to determine great skills by talking to a candidate, they’re stuck with using other tools to try to weed out the people they consider weaker.
      Where I have a problem is when they ask questions that are not realistic in the hopes of getting some insight about who you are. Since they rarely have a clue how to interpret the results, that becomes a futile effort that often puts the wrong candidate at the top of the hire-list.

      I like your idea about discussing a problem and seeing how the candidate responds. Ultimately, that’s probably the way to go. If the response is similar to what you were thinking, or can otherwise see how that would help solve a real-life problem, that you found a great candidate for the analysis part of the job—and the rest can be learned if it’s just a matter of picking up a simple skill or two or brushing up on something or looking it up on the Internet.

    • David Levine

      I would rather have a interview with a test that shows technical knowledge than a interview that asks what is my worst flaw, or some nonsense question that is expected to show my ability to think outside of the box.
      If the employer is trying to hire a technical person, they need some way to evaluate the candidates. I have seen many engineers without a clue.

  3. Greta Ward

    Call me naive but I personally think it is important to make it clear to the candidate what the interview is about ahead of time, e.g. “we want to see how you problem solve”, “we want to see if you can use language X effectively”, “we want to see how you solve problems in a group setting”. I had a panel whiteboard interview that could also classify as a stress test (I was told this would be on language X and it was not (which I believe was deliberate)). I found it too hard to decide how to deal with the technical questions I was unprepared for at a whiteboard (with no references!) and at the same time trying to figure out why I was set up for this so I could address their concerns.

  4. Dejay Clayton

    I’ve been in this position a few times before as an interviewee. My replies did not start with a disclosure that I already knew the solutions; they did start with a high level explanation of what topics the problem regarded, and possible approaches, followed by a discussion of
    one or three good candidate solutions. This is exactly the type of response I would give under terms of employment, and therefore accurately reflects the type of skills I bring to employers.

  5. I disagree with this advice. Increasing your knowledge base of possible problems improves your skill-set, and makes you arguably a better employee. Seeing the problem before hand does not make you less able to explain how you got there. It generally does give you more confidence in the explanation. You do not have to play dumb, you just have to methodically explain your steps.

    • It depends on what sort of problem you’re talking about. If you’re talking about a problem like, “Design an algorithm to find the longest palindrome in a string,” seeing the problem *does* make you less able to explain how you got there. Your interviewer is not able to see the problem solving process. These are the sort of problems I’m talking about.

    • For “Design an algorithm to…” type questions, your interviewer is looking to watch how you solve a problem. Part of that evaluation is based on how long it takes you to solve it.

      As I explained in the article, if you just spit out the right answer, then the interviewer will know that you knew the question. Worst case, your interviewer will see you as dishonest and reject you for that. Best case, your interviewer will know that you knew the answer and not give you any credits for solving it “quickly.”

      So, candidates think, “I’ll pretend I don’t know the solution by struggling a little bit, but then I’ll still end up ‘solving’ it very quickly.”

  6. I’m sorry but this article is rubbish. Interviewers fall for these types of tricks all the time. Most interviewers have no training or experience in interviewing so, naturally, they tend to hire the guy who is good at interviewing, not necessarily the job.

  7. I’ve been interviewing candidates for technical roles for the past few months off and on, and I can tell you from experience that (at least in our company) we don’t expect candidates to know all the answers. In fact, we expect them to miss some. Questions of any type are intended to probe for skill level. Interviews are conducted in a respectful and professional manner, so whether or not we technical screen is not very relevant with regards to “respecting the candidate”. The best candidates have some technical ability combined with tenacity, common sense (surprisingly rare these days), intelligence, and display a good attitude toward work. Most of the time, we are able to do a pretty good job of gauging those metrics with the assistance of a reputable recruiting firm and multi-staged interview process.

  8. The best response I’ve seen from a candidate (who we eventually hired) was something along the lines of: “I’ve seen a similar problem to this before … here is how I handled it” then proceeded to detail the process, ending in the correct solution.

  9. Unfortunately, it doesn’t matter… It’ll be one of two things… If you “dumb it down” you’ll be viewed as dumb – if you “play it smart” and answer the question – if the person sitting in front of you doesn’t know the answer, then you’re “more” qualified than they are – thus, eliminating you from the job all together!
    It’s called “over-qualified” Been there, done that, don’t get the job for being “more” than what my resume says… So while I “dumb down” my resume to get an interview, when I open my mouth, I’m in trouble anyway!

  10. Ok lets talk about ethics . Employers would NEVER use facebook to look at a prospective hire, as the facebook post may contain EOC protected data. So acting in an interview.

    • Not sure how that’s relevant to this post, but, I’m not sure that’s true. Some employers definitely do look up candidates on Facebook.

      I agree though that the whole “ZOMG DON’T HAVE ANYTHING PERSONAL ONLINE” stuff is way overblown. Most employers, especially in tech, don’t really care what you have online, provided its reasonable. A picture of you with a beer is not going to concern most employers (even if you’re underage).

  11. Gayle or anyone else, would you have a problem with someone who, when asked an interview question that they knew the optimal solution to, merely gave the optimal solution, without trying to pretend they are solving the problem? After all, the candidate cannot know what the interviewer’s motivation is for asking the question — whether what is being tested is knowledge, problem solving ability, etc.

    Incidentally, this is one reason I don’t ask questions on interviews for which there are well-known optimal solutions that can be (and often are) memorized. Instead, I would rather ask about a candidate’s approach to a particular problem he or she encountered in a past job or project, then vary the parameters somewhat to assess the candidate’s understanding of resource management, scalability, robustness, etc. I find this is more valuable in assessing how the candidate would actually do on the job. YMMV.

    • It depends on the situation.

      When I ask a reasonably difficult algorithm problem, it’s pretty obvious that I’m not testing knowledge. I’m testing problem solving ability. I would find it *very* hard to believe that a candidate actually thought that I was testing to see if he/she knew the answer to the problem.

      So, given that, I would have a bit of an issue with it. It would raise a *potential* red flag on honesty.

      For algorithm problems that are super well-known (e.g., “remove duplicates in an array”), I think it’s fine for candidates to just spit out the answer. There’s really no problem solving component to them and everyone has heard those questions. They’re really coding questions, not problem solving questions.

      • Well, it may be obvious to you, but why should it be obvious to the candidate? Especially if the candidate is interviewing with many companies (not unusual for a recent grad or someone who is unemployed).

        When I was a grad student, in one of my midterms, the professor gave a problem that could have been answered with one of the algorithms he presented in class. It was a very long algorithm, however, which many people could very well have memorized (and perhaps some did). However, during the exam, he asked that people give an algorithm (as opposed to writing down the one presented in class) that need not necessarily be a polynomial-time algorithm, which was a relief to some people.

        Anyway, what I’m trying to say is if expectations are clarified at the beginning of the interview, it’s much less likely that people will have the type of angst about interviews that exists now. IMO, there are many ways to do this without putting candidates in positions where they have to ascertain the motive of the interviewer. Candidates are nervous enough as it is, wanting to make a good impression — they should be given the benefit of the doubt when presenting the solution to a problem, IMO.