Incompetent Interviewers

Amazon I3JQHz
Aug 10, 2018 20 Comments

Have you guys ever encountered incompetent interviewers who cannot understand their own interview questions?

I recently interviewed with Apple. The question is like this: given a list of events 1 to n. Each event i has a probability P_i. And they asked me to find a subset of events with weight constraint to maximize the probability of the combined event.

Of course I don’t know how to solve it without knowing the properties of these events. Then I asked the interviewer if the events are independent. The interviewer was just confused and don’t know what “independent” means.

Then I asked if we can add the probabilities. (It works for exclusive events and usually a good approximation.) Then the interviewer got mad immediately and accused me how I can add probabilities because the sum may be larger than 1. He even accused me if I know probability theory at all. (I got A+ for my probability class from MIT by the way)

Now without any useful input, I try to solve the problem to maximize the probability for the worst case scenario. The solution is to pick the events with largest probability greedily. The he got mad again and ask me why I can chose a event with 0.91 probably over two events with 0.9 probability.

In the end, I think he assumes the events are independent without knowing what independence is. I provided a correct solution for independent events in the last 3 minutes or so but I still got rejected.

Has anyone encountered incompetent interviewers like this? How do you deal with them? I feel I don’t want to work with this kind of people anyway. But I am still upset especially because I was accused by someone who don’t know what independent events are.

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TOP 20 Comments
  • Tesla $&.*
    You got off easy. Imagine working with him.
    Aug 10, 2018 0
  • Dropbox Dropbox1
    You sound like an equally terrible interviewee based on how bitter you are.
    Aug 10, 2018 2
    • not really
      Aug 10, 2018
    • Amazon I3JQHz
      OP
      I tried my best to ask questions and get information needed to solve the problem. When I finally understood that he just secretly assumed that those are independent events, I provided at least the outline of the correct algorithm. I don’t see any way I can do better except that I happened to make the same assumption with the interviewer.
      Aug 10, 2018
  • Qualcomm
    Kimjeller

    Qualcomm

    PRE
    Qualcomm, AMD
    Kimjellermore
    Shouldn’t you have demanded that if there is no information regarding the independence of events then the question is incomplete. It becomes a pissing contest and him not knowing independence means that he doesn’t know probability. You should have given him P(A|B) classic equation as a litmus test.
    Aug 10, 2018 0
  • Apple Rjcricksnf
    Sorry about your experience. Still don’t understand the qs. Glad I did not encounter this qs during my interview.
    Aug 10, 2018 0
  • Tesla LEETCODER
    This sounds like a variant if coin change DP problem. Anyway yea we all have bad interview experiences. Can't do much tho.
    Aug 10, 2018 2
    • Amazon I3JQHz
      OP
      Yup. If the events are exclusive, it’s a regular knapsack problem. If they are independent, you need to do some math and you can transform it into a knapsack problem.

      If we don’t know anything about the problem, we should use greedy algorithm and pick the ones with highest probability.
      Aug 10, 2018
    • wtf ru guys talking about?
      Aug 10, 2018
  • Apple / Eng JobsHand
    Apple usually drags whatever available engineer into interviews. We do not have a formal interview training program. So unfortunately you might get a bad interviewer from time to time. Sorry to hear about your experience. Be sure to tell the recruiter and maybe they can take that individual off the rotation.
    Aug 10, 2018 0
  • New / Eng dKgt74y
    Was this on the macbook team? I had an interviewer first give me a problem I had known to never before been solved, and then he asked me a problem with which his answer was incorrect.
    Aug 10, 2018 2
    • Amazon I3JQHz
      OP
      No. It’s a team working on a failing iOS app.
      Aug 10, 2018
    • Apple Rjcricksnf
      Lol. What app is that?
      Aug 10, 2018
  • Uber Xbsnwb
    I don’t see how you could be rejected based on a single bad loop that you got the answer for by the end anyway. There must be more to this.
    Aug 10, 2018 1
    • Amazon I3JQHz
      OP
      I can imagine what he wrote about me: “This candidate has zero knowledge about probability theory because he think it’s OK to add probabilities. Not honest about his background because he claimed he was an expert in probability theory.”
      Aug 11, 2018
  • New
    uNSi04

    New

    BIO
    New grad
    uNSi04more
    I don't have much experience in this but last September I had an interview with Google where the interviewer didn't say a thing. All of their recruitement videos / events say that the interviewer will step in if you speak and say your thought process while you code. My first solution was wrong and instead of pointing that out he asked the follow up question which led me to spend the whole interview building on something wrong and even said that I did well and demonstrated that I could solve the problem. I realized my mistake right after the interview and as I expected I got a rejection. I know it's not his fault that I miscalculated but had he just said something I could've fixed it
    Aug 10, 2018 1
    • Amazon I3JQHz
      OP
      I think in your case the interviewer may not even know you were wrong at the time. I have been rejected by Facebook because my algorithm is correct but different from the standard solution and the interviewer struggled to understand. I have to spend the whole time teaching the interviewer and end up having no time for follow-ups.
      Aug 10, 2018
  • which country was he from? india or china ?
    Aug 10, 2018 1
    • Amazon I3JQHz
      OP
      He is white and speaks American English.
      Aug 10, 2018
  • Microsoft fuckbat
    Don't worry, you should have rejected him first. More power to you
    Aug 10, 2018 0

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