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This is why this whole interview thing is so absurd. The amount of days lost by engineers to relearn obscure algorithms and training on leetcode while we could

This is why this whole interview thing is so absurd. The amount of days lost by engineers to relearn obscure algorithms and training on leetcode while we could be coding for things that are actually useful.

gameswithgo 8y ago
obscure algorithms are useful. it isn't a perfect system but its better than what most people propose as alternatives, which is to just have an ad hoc conversation. testing whether someone is willing to prepare for a thing is a relevant work skill test too.
- pmiller2 8y ago
  There’s a vast difference between, say, preparing for a school exam and preparing for a job interview. In the former, you know in advance what material will be tested. Job interviews are more like PhD comprehensive exams, or professional licensing exams. I know a lot of working professionals who are good at their jobs, yet admit they wouldn’t be able to pass the license exam today.
- 1000units 8y ago
  The elephant in the room is that it's a surrogate for an IQ test, since those are illegal.
  - thedufer 8y ago
    It is not illegal to use IQ tests as part of a job screening (in the US). It is illegal to screen in a way that is both discriminatory and not proven to correlate with job performance, but that applies equally to both IQ tests and algorithms questions.
    - 1000units 8y ago
      IQ is proven to correlate with performance in virtually everything, so I'm not sure where you're going with that. If I require all prospective engineering hires to prove explicitly that they have an IQ of at least 135, I will get sued. Do you think this is false?
      - thedufer 8y ago
        Obviously I do not think that is false; you can get sued for literally anything. Do I think you would lose? Depends on whether you've done the research showing that 135 is an important cut-off. To turn this around, can you point at the law that makes IQ a protected class or whatever you're claiming it is? I'm not going to have much luck proving a negative - Russell's teapot and all that.
- majormajor 8y ago
  There seems to be an assumption in these discussions that everyone has to prepare for these things in equal amount. But that's not the case. (The counter to that is that if people can relatively-easily (single-digit days) cram for your interview, you're still not going to be effectively screening for at-hand pre-existing familiarity/knowledge.)
- pcwalton 8y ago
  Go search for "Knights on a Keypad" (a formerly-common Google interview question). Trying to imagine any situation in which the solution would be useful is harder than the problem itself.
  - joshuamorton 8y ago
    You mean that you can't imagine when a memorized graph traversal would be useful? I find that hard to believe.
    - pcwalton 8y ago
      I have actually implemented memoized graph traversals for work (unlike most programmers). To begin with, I see no point in asking this when I could ask how to implement trait checking in Rust (what I had to use memoized graph traversals for), which a practitioner will find much more intuitive. Moreover, memoized graph traversals don't get you full credit on this question. There's a dynamic programming solution, and in fact the ideal solution is one using matrix math, which is ludicrously divorced from anything most programmers would ever see.
  - kyralis 8y ago
    If you're trying to find a situation where that exact solution is going to be useful, you're not thinking about the problem from the right perspective. Handled correctly, a problem like this answers several questions: 1) Can you correctly break down a problem like this into its components parts? 2) Can you recognize the overall class of problems that this falls into? 3) Can you transform this specific problem into the more general class so that you can solve it in a known fashion? 4) Can you think about and implement the movement? 5) Can you communicate while you're doing the above? No one cares about solving that particular problem. But the answers to the above really are relevant. Being able to map novel problems onto known solutions is absolutely a skill that any competent software engineer needs to have. "Oh, you want me to do X? That looks a lot like Y, this thing we've already solved; maybe I can just implement it in the same fashion (or re-use our existing system!)" I'm not saying that this particular problem is a wonderful example, or that I'd use it in my own interviews. But this overall class of problems really does have a place in interviewing when it's handled well by the interviewers, and arguments against it on the basis of the specific problem being irrelevant are really rather missing the point.
- stone-monkey 8y ago
  >testing whether someone is willing to prepare for a thing is a relevant work skill test too. Is it, though? I could understand if algo questions had some relation to the work you're doing, but your comment on why they're good is independent of the actual material. If we replaced the algorithm question interview with an interview testing obscure presidential facts, would it really be a useful test to have devs take? I guess it is a relevant work skill test in that you get people willing to put the work in/game the system, but it doesn't seem to be much of (if at all) an improvement from ad hoc conversations.
- SomeHacker44 8y ago
  Knowing the existence of, and understanding the performance characteristics of a broad range of algorithms is, to my mind, a much more useful set of working knowledge than the details of any individual algorithm. The latter can always be looked up. It is harder to find out the former and much better to say “yes, there is an algorithm such-and-such that may be applicable here, let me spend 5 minutes checking that.” In my experience, anyway.
  - hotcrossbunny 8y ago
    Broadly speaking, that used to be how design patterns were often treated in interviews. Could you recognise, describe, code, discuss pros, cons and applicability for pattern X in given circumstance. Pretty easy stuff to cram unfortunately, which may be why they may have fallen out of favour in recent times as proxy measure for brains, but depending on the role in question that sort of material was often more likely to be useful in the job than a similarly broad knowledge of algorithms
- wolco 8y ago
  What about using a real job related task. If they can do that they probably can do the job.
- warp_factor 8y ago
  So you are saying that companies are hiring people that are willing to prove that they can put "a lot of work" into preparing for interviews that have no relevance to the actual work? I can see that as a valid point, as a way to filter lazy individuals. (In the same way that a college degree is more a way to prove that you can sustain X years of learning things without dropping out). But it will also filter out everyone that is opinionated enough to not do that stupid preparation work, and you will end up with sheep coders that will always follow the rules. Looking at Google, Facebook etc, this might already be the case. I will even go so far to say that they prefer those type of obedient coders than the ones that ask too many questions and get too creative.
  - matwood 8y ago
    No relevance would be like when I took the GRE for grad school. I studied things that had zero relevance to the CS program I ended up attending. Reviewing algorithms for interview prep at least has some relevance to programming. While a candidate may not use that exact algorithm in their day to day job, they are creating ad hoc algorithms all day long. With that said, I don't think time pressure, white boarding algorithms is a very good job performance predictor.
AnimalMuppet 8y ago
Exactly. As I said before, in a world where both Google and Knuth exist, they aren't hiring me to be a algorithm reference book.

gameswithgo 8y ago

obscure algorithms are useful. it isn't a perfect system but its better than what most people propose as alternatives, which is to just have an ad hoc conversation. testing whether someone is willing to prepare for a thing is a relevant work skill test too.

pmiller2 8y ago
There’s a vast difference between, say, preparing for a school exam and preparing for a job interview. In the former, you know in advance what material will be tested. Job interviews are more like PhD comprehensive exams, or professional licensing exams. I know a lot of working professionals who are good at their jobs, yet admit they wouldn’t be able to pass the license exam today.
1000units 8y ago
The elephant in the room is that it's a surrogate for an IQ test, since those are illegal.
- thedufer 8y ago
  It is not illegal to use IQ tests as part of a job screening (in the US). It is illegal to screen in a way that is both discriminatory and not proven to correlate with job performance, but that applies equally to both IQ tests and algorithms questions.
  - 1000units 8y ago
    IQ is proven to correlate with performance in virtually everything, so I'm not sure where you're going with that. If I require all prospective engineering hires to prove explicitly that they have an IQ of at least 135, I will get sued. Do you think this is false?
    - thedufer 8y ago
      Obviously I do not think that is false; you can get sued for literally anything. Do I think you would lose? Depends on whether you've done the research showing that 135 is an important cut-off. To turn this around, can you point at the law that makes IQ a protected class or whatever you're claiming it is? I'm not going to have much luck proving a negative - Russell's teapot and all that.
majormajor 8y ago
There seems to be an assumption in these discussions that everyone has to prepare for these things in equal amount. But that's not the case. (The counter to that is that if people can relatively-easily (single-digit days) cram for your interview, you're still not going to be effectively screening for at-hand pre-existing familiarity/knowledge.)
pcwalton 8y ago
Go search for "Knights on a Keypad" (a formerly-common Google interview question). Trying to imagine any situation in which the solution would be useful is harder than the problem itself.
- joshuamorton 8y ago
  You mean that you can't imagine when a memorized graph traversal would be useful? I find that hard to believe.
  - pcwalton 8y ago
    I have actually implemented memoized graph traversals for work (unlike most programmers). To begin with, I see no point in asking this when I could ask how to implement trait checking in Rust (what I had to use memoized graph traversals for), which a practitioner will find much more intuitive. Moreover, memoized graph traversals don't get you full credit on this question. There's a dynamic programming solution, and in fact the ideal solution is one using matrix math, which is ludicrously divorced from anything most programmers would ever see.
- kyralis 8y ago
  If you're trying to find a situation where that exact solution is going to be useful, you're not thinking about the problem from the right perspective. Handled correctly, a problem like this answers several questions: 1) Can you correctly break down a problem like this into its components parts? 2) Can you recognize the overall class of problems that this falls into? 3) Can you transform this specific problem into the more general class so that you can solve it in a known fashion? 4) Can you think about and implement the movement? 5) Can you communicate while you're doing the above? No one cares about solving that particular problem. But the answers to the above really are relevant. Being able to map novel problems onto known solutions is absolutely a skill that any competent software engineer needs to have. "Oh, you want me to do X? That looks a lot like Y, this thing we've already solved; maybe I can just implement it in the same fashion (or re-use our existing system!)" I'm not saying that this particular problem is a wonderful example, or that I'd use it in my own interviews. But this overall class of problems really does have a place in interviewing when it's handled well by the interviewers, and arguments against it on the basis of the specific problem being irrelevant are really rather missing the point.
stone-monkey 8y ago
>testing whether someone is willing to prepare for a thing is a relevant work skill test too. Is it, though? I could understand if algo questions had some relation to the work you're doing, but your comment on why they're good is independent of the actual material. If we replaced the algorithm question interview with an interview testing obscure presidential facts, would it really be a useful test to have devs take? I guess it is a relevant work skill test in that you get people willing to put the work in/game the system, but it doesn't seem to be much of (if at all) an improvement from ad hoc conversations.
SomeHacker44 8y ago
Knowing the existence of, and understanding the performance characteristics of a broad range of algorithms is, to my mind, a much more useful set of working knowledge than the details of any individual algorithm. The latter can always be looked up. It is harder to find out the former and much better to say “yes, there is an algorithm such-and-such that may be applicable here, let me spend 5 minutes checking that.” In my experience, anyway.
- hotcrossbunny 8y ago
  Broadly speaking, that used to be how design patterns were often treated in interviews. Could you recognise, describe, code, discuss pros, cons and applicability for pattern X in given circumstance. Pretty easy stuff to cram unfortunately, which may be why they may have fallen out of favour in recent times as proxy measure for brains, but depending on the role in question that sort of material was often more likely to be useful in the job than a similarly broad knowledge of algorithms
wolco 8y ago
What about using a real job related task. If they can do that they probably can do the job.
warp_factor 8y ago
So you are saying that companies are hiring people that are willing to prove that they can put "a lot of work" into preparing for interviews that have no relevance to the actual work? I can see that as a valid point, as a way to filter lazy individuals. (In the same way that a college degree is more a way to prove that you can sustain X years of learning things without dropping out). But it will also filter out everyone that is opinionated enough to not do that stupid preparation work, and you will end up with sheep coders that will always follow the rules. Looking at Google, Facebook etc, this might already be the case. I will even go so far to say that they prefer those type of obedient coders than the ones that ask too many questions and get too creative.
- matwood 8y ago
  No relevance would be like when I took the GRE for grad school. I studied things that had zero relevance to the CS program I ended up attending. Reviewing algorithms for interview prep at least has some relevance to programming. While a candidate may not use that exact algorithm in their day to day job, they are creating ad hoc algorithms all day long. With that said, I don't think time pressure, white boarding algorithms is a very good job performance predictor.

AnimalMuppet 8y ago

Exactly. As I said before, in a world where both Google and Knuth exist, they aren't hiring me to be a algorithm reference book.