4 ms·

Thank you for the example, but this is not a generalized problem, and is very specific to your domain, so it would be silly to receive such a question from comp

Thank you for the example, but this is not a generalized problem, and is very specific to your domain, so it would be silly to receive such a question from companies that are not your company, which I have had happen. If I were applying for your company, I would expect to have to implement an algorithm like this on the job, but I don't see why I should have to know it to get the job. As long as I was capable of implementing algorithms as described, wouldn't that be the most important factor?

chillacy 11y ago
How would you demonstrate that you're capable of implementing that algorithm? Isn't the best way to have them implement that algorithm? (I will admit that this is best done when the candidate has their favorite text editor and internet, and I have had an interview in the past where this was the case, which went well)
- dclowd9901 11y ago
  I would suggest that you provide the algorithm in process or through formulae, and have the candidate implement it. That's what they'll be doing anyway.
  - chillacy 11y ago
    What kind of job do you have where someone tells you the algorithm? I can't imagine my PM saying "Let's count recent events by storing it in a hashmap and using a linked list to track which elements have expired, can you code that up?" Instead, the PM might say "We need a system which can count how many unique events of each type has occurred in the last 100k requests, with small impact to time, high accuracy, and up to 100mb of space" But even that would be unusually specific. It would usually be: "the service breaks sometimes, can you figure it out?" And then the engineers figure out that it's because of unusual event distributions, and they figure out what needs to be done, how much space / time they can afford to do it, etc. For instance, do you trade off accuracy by having a periodic job flush old events out of the map? Do you quantize by time to save space at the cost of resolution? That's what I do at my job, and that's the kind of question I see in interviews. If a candidate is expecting to have the algorithms dictated to them, then I would not consider them to be a software engineer.. coding up a program from a specification would have been a technician's job 30 years ago (now largely automated by compilers, synthesizers (for HDLs), and other tools). The software engineer should be coming up with solutions, which often involve using algorithms and data structures.
    - dclowd9901 11y ago
      And, again, I ask "are you under some kind of arbitrary time constraint when you have to create a novel problem solving approach?" Listen, most data theory problems have been solved, but for the ones that haven't, in work, we're asked to come up with a solution, but not in any weird arbitrarily short amount of time. If your goal is to simply know how someone explores a problem, fine I guess. I don't agree with your approach but I can see your point. But if you expect a working implementation, that's unreasonable in my opinion and I believe you'll be rejecting many fine candidates using that method.
      - chillacy 11y ago
        > arbitrary time constraint Don't you have release deadlines, even if they're measured in weeks? Depending on the complexity of the problem, I've been expected to produce code. That tends to be tricky and I don't always get it 100%, but I've not finished my code and gotten just the general direction, and still passed (received the offer). > you'll be rejecting many fine candidates using that method. I could see that being true. Without knowing what kind of company you work at I wouldn't know. Since I work in a big tech company who interviews in this fashion, all my coworkers who I'd consider fine candidates have passed this (partly arbitrary) bar. It's not something I was good at, but I decided that I wanted to work at a big tech company, so I decided to play the interview game.
infinite8s 11y ago
And how would the company know you were capable of implementing algorithms as described? Perhaps by asking you during the interview how you might go about implementing it?
- dclowd9901 11y ago
  Precisely!

chillacy 11y ago

How would you demonstrate that you're capable of implementing that algorithm? Isn't the best way to have them implement that algorithm? (I will admit that this is best done when the candidate has their favorite text editor and internet, and I have had an interview in the past where this was the case, which went well)

dclowd9901 11y ago
I would suggest that you provide the algorithm in process or through formulae, and have the candidate implement it. That's what they'll be doing anyway.
- chillacy 11y ago
  What kind of job do you have where someone tells you the algorithm? I can't imagine my PM saying "Let's count recent events by storing it in a hashmap and using a linked list to track which elements have expired, can you code that up?" Instead, the PM might say "We need a system which can count how many unique events of each type has occurred in the last 100k requests, with small impact to time, high accuracy, and up to 100mb of space" But even that would be unusually specific. It would usually be: "the service breaks sometimes, can you figure it out?" And then the engineers figure out that it's because of unusual event distributions, and they figure out what needs to be done, how much space / time they can afford to do it, etc. For instance, do you trade off accuracy by having a periodic job flush old events out of the map? Do you quantize by time to save space at the cost of resolution? That's what I do at my job, and that's the kind of question I see in interviews. If a candidate is expecting to have the algorithms dictated to them, then I would not consider them to be a software engineer.. coding up a program from a specification would have been a technician's job 30 years ago (now largely automated by compilers, synthesizers (for HDLs), and other tools). The software engineer should be coming up with solutions, which often involve using algorithms and data structures.
  - dclowd9901 11y ago
    And, again, I ask "are you under some kind of arbitrary time constraint when you have to create a novel problem solving approach?" Listen, most data theory problems have been solved, but for the ones that haven't, in work, we're asked to come up with a solution, but not in any weird arbitrarily short amount of time. If your goal is to simply know how someone explores a problem, fine I guess. I don't agree with your approach but I can see your point. But if you expect a working implementation, that's unreasonable in my opinion and I believe you'll be rejecting many fine candidates using that method.
    - chillacy 11y ago
      > arbitrary time constraint Don't you have release deadlines, even if they're measured in weeks? Depending on the complexity of the problem, I've been expected to produce code. That tends to be tricky and I don't always get it 100%, but I've not finished my code and gotten just the general direction, and still passed (received the offer). > you'll be rejecting many fine candidates using that method. I could see that being true. Without knowing what kind of company you work at I wouldn't know. Since I work in a big tech company who interviews in this fashion, all my coworkers who I'd consider fine candidates have passed this (partly arbitrary) bar. It's not something I was good at, but I decided that I wanted to work at a big tech company, so I decided to play the interview game.

infinite8s 11y ago

And how would the company know you were capable of implementing algorithms as described? Perhaps by asking you during the interview how you might go about implementing it?

dclowd9901 11y ago
Precisely!