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Ask HN: Is asking obscure algorithms any test of programming ability?

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Ask HN: Is asking obscure algorithms any test of programming ability?

#1

Post by raj_m »

A friend of mine is being interviewed for Big 4. In the first round of screening, (s)he was asked about a linear time algorithm to find all the maximum element in a sliding window in an array.

Now this is a simple problem for anyone who has taken any DS or Algo Undergraduate level class since it involves the important concept of the priority queue. However, it is my understanding that to do this in a linear time is neither trivial nor straightforward and unless that person is really gifted. (Its something called Monotone Priority Queue which is not present in any standard Algorithm textbook) So my question to the general populace is: Are knowing obscure algorithms like this any test of a person's programming ability ?

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#4

Post by raj_m »

Etheryte wrote: post #2

The test isn't about whether you know the algorithm – quite the opposite. The test is about seeing how you approach a problem you haven't (possibly) solved before.

That's an interesting observation. So what you are saying is that if I make sufficient headway into the problem without providing the most efficient answer, it should be fine?

There are rumors that unless you are spot on perfect in Big 4 interviews, they wont advance you.

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#5

Post by perfmode »

raj_m wrote: post #4
Etheryte wrote: post #2

The test isn't about whether you know the algorithm – quite the opposite. The test is about seeing how you approach a problem you haven't (possibly) solved before.

That's an interesting observation. So what you are saying is that if I make sufficient headway into the problem without providing the most efficient answer, it should be fine? There are rumors that unless you are spot on perfect in Big 4 interviews, they wont advance you.

It depends on the aptitude for problem solving that the interviewer observes in the process.

It's about understanding the computer science fundamentals in order to keep your code from burning up 1000's of cores due to asymptotically-poor characteristics.

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#6

Post by csnewb »

Etheryte wrote: post #2

The test isn't about whether you know the algorithm – quite the opposite. The test is about seeing how you approach a problem you haven't (possibly) solved before.

I mean, aren't those algorithms developed by CS professors/researchers/Ph.D's/mathematicians? As a junior developer I seriously doubt I'd even approach the problem the same way as the super smart person who developed that algorithm.

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#7

Post by sdflkd »

raj_m wrote: post #4
Etheryte wrote: post #2

The test isn't about whether you know the algorithm – quite the opposite. The test is about seeing how you approach a problem you haven't (possibly) solved before.

That's an interesting observation. So what you are saying is that if I make sufficient headway into the problem without providing the most efficient answer, it should be fine? There are rumors that unless you are spot on perfect in Big 4 interviews, they wont advance you.

It all depends on the interviewer. Anyone claiming different is selling you bullshit. The purpose of the interview and how they are actually used in practice is all on the interviewer.

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#8

Post by Chyzwar »

Normally, you would interview someone on problems that you want to solve. You would want to hire someone that will help with business challenges by providing specific programming expertise. Requiters do keywords search for a reason.

Problem with Big 4 is that these problems are on such scale that you cannot possibly expect anyone knowing how to solve them. In the same sense your experience is irrelevant because these companies have internal tooling and frameworks that are mostly specific to problem domain.

Algorithms questions test two things: 1. How you think under pressure. (culture fit) 2. Dedication, because you need to waste weeks on preparations (corporate slave).

Re: Ask HN: Is asking obscure algorithms any test of programming ability?

#10

Post by db48x »

db48x wrote: post #9

If you believe some reports, it doesn't matter what is covered in an interview; it's no better than a lottery regardless.

Also, any test that you ace has not completely characterized your actual skill level; all it tells you is that you're above the skill range measured by the test. You might be a little bit above, or far above, that upper bound. Maybe they've decided to have one really hard question that it's unlikely anyone will answer correctly, but if they get someone who can answer it then they know they've found someone really suited for the job.

Or it could be a mistake, and it was just bad luck that your friend got an interviewer who doesn't know how to interview, and asked a question that about a subject that they're intimately familiar with, but is too hard compared to what is asked by other interviewers.

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