The software development final exam: Algorithms and Data Structures • Hacker News Board

Re: The software development final exam: Algorithms and Data Structures

#81

Post by shrughes » Mon, Oct 08, 2012, 12:56 PM UTC

amix wrote: post #7

While I can answer some of these questions (and could answer them all a few years ago while attending university) this kind of knowledge is simply not something that I use on a daily basis. I also doubt that many others developers use it unless they have very specialized jobs. These kind of questions should not be the only basis of the software development final exam. In software development problem solving, communic…

They're the sort of thing I use on a daily^H^H^H^H^Hfrequent basis. The questions are not asking trivia questions or looking for knowledge, they're asking questions whose answers can be figured out.

Re: The software development final exam: Algorithms and Data Structures

#82

Post by andrewf » Mon, Oct 08, 2012, 12:58 PM UTC

But you should Google afterwards so you can feel like a right ponce for confusing Big-Theta and Big-O.

Re: The software development final exam: Algorithms and Data Structures

#83

Post by ataggart » Mon, Oct 08, 2012, 1:03 PM UTC

irahul wrote: post #75

ataggart wrote: post #17

I wonder about the utility of an exam that one can ace with five minutes of googling.

> I wonder about the utility of an exam that one can ace with five minutes of googling. I won't debate the utility of the exam, but the majority of the tests I have taken can be aced with five minutes of googling.

Likewise for myself. Though I suspect that it's because testing for memory is easier than testing for knowledge, especially when one can simply assume that the former accomplishes the latter.

Re: The software development final exam: Algorithms and Data Structures

#84

Post by flatline » Mon, Oct 08, 2012, 1:05 PM UTC

dscrd wrote: post #68

hermannj314 wrote: post #42

I have no educational training in computer science, but I work as a software developer. I could not answer any of those questions, literally 0 out of 5. 1. Is O(2^n) equal to O(3^n)? Why? I have absolutely no idea what that means. But I did have to answer this question: why does the application crash? "Oh...that's because the developer that was pontificating yesterday about how heap operations behave asymptotically f…

Hmm, does all this imply that a blue-collar IT-workers' class is rising? When I was working during the summers at construction sites in my youth, I noted that everybody all the time complained about the impractical decisions the engineers and architects had made, and grumbling that they had to be there to fix them. Would they have been happier if they wouldn't have been needed at all? (disclaimer: I tend to change my…

Interesting analogy. I think it more strongly implies that for the type of applications most frequently written, general intelligence and experience trump theoretical knowledge. Honestly the education you get from a BS in comp sci (the level of knowledge the post addresses) isn't going to qualify you for much more than the guy who has 4 years of experience on his résumé. Much less in some circumstances actually. This is a strange field.

Re: The software development final exam: Algorithms and Data Structures

#85

Post by esrauch » Mon, Oct 08, 2012, 1:06 PM UTC

stonemetal wrote: post #74

hobbyist wrote: post #60

I wanted to ask this question regarding big O notation. When we say f(n) = O(g(n)) all we mean to say is that f(n) <= c(g(n)) with other constraints. My question is, why do we have an equal to sign, why is f(n) equal to O(g(n)).. they could have made up a new symbol to establish such a relationship... The reason why I think so is because I see equal to as a transitive relationship.. So, if a = b and c = b, then a = c…

why is f(n) equal to O(g(n)).. they could have made up a new symbol to establish such a relationship... It is an equality relationship why would they need a new symbol? f(n) = O(g(n)) .. n^2 = O(n^2) and n = O(n^2), so n = n^2 which is not making any sense You are right it doesn't make any sense. Try n^2 = O(Selection_sort(n)),O(Bubble_sort(n)) = O(Selection_sort(n)), n^2 = O(Bubble_sort(n)). Nice and transitive the…

Unfortunately this answer is incorrect and is a common misunderstanding of big-O. Selection sort is typically stated to be O(n^2), which is true, but the way that O works is that it's a bound from above. It means "the set of functions that asympotically are guaranteed to not take more time than".

Selection sort is also O(n^3) and O(n!) and O(n^2 log log log log log n). The correct operator for saying that f(x) is O(n) is the set exists operator ∊. O(n^2) is a set of functions that is a strict subset of the set of functions that are in O(n^3).

Selection sort is only big-theta(n^2), which indicates both the bounds are tight (eg for Selection sort it is true that it's asymptotic behavior is both f(n) = bn^2 + n.

Re: The software development final exam: Algorithms and Data Structures

#86

Post by stripe » Mon, Oct 08, 2012, 1:07 PM UTC

Too bad the author does not care to ask for the more important bits of developing software but devulges into questions a web crawler could answer. Creating elitisim (by offensively downgrading any developer who cannot answers these questions or simply has to look up an answer) does benefit no one. Developing software is so much more than details of an algorithm, of an operating system or a network topology. It is about needs, about requirements, users, customers, support, processes, technology and the list goes on and on. Simply put, he is not asking questions for software developers but for programmers.

Re: The software development final exam: Algorithms and Data Structures

#87

Post by huherto » Mon, Oct 08, 2012, 1:07 PM UTC

ataggart wrote: post #37

cperciva wrote: post #21

Earlier quoted context omitted.

I'm not going to be handing out degrees based on these. If you mean the utility of the specific questions, the point is that knowing these things is indicative of your general level of knowledge in certain areas.

>knowing these things is indicative of your general level of knowledge in certain areas. Very possibly. But is knowing the same as remembering? Compare remembering the specific value of quicksort's worst case to knowing that some sort algorithms are better than others when, say, the input is likely to already be sorted, and that you should go crack open CLRS if you dont recall which.

Quicksort is usually randomized. So it is not a matter of the order of the elements, it is a matter of very bad luck on selecting your pivots. So even if worst case performance is very bad it is very unlikely. But you have to understand why.

You probably will never implement quicksort, but it is useful to know, how it works, as you may be able to use some of the ideas on your own algorithms. Quicksort is also beautiful, so it can be a good inspiration on writing good software.

Re: The software development final exam: Algorithms and Data Structures

#88

Post by Aloush89 » Mon, Oct 08, 2012, 1:09 PM UTC

modernerd wrote: post #19

"If you can't answer the majority of the questions on these four papers, and you're working or intend to work as a software developer, you should ask yourself why — most likely you're either you're missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter." [1] I'm a self-taught front end web developer who didn't have a traditional computer s…

You can check the courses taught on coursera:

  - Algorithms part I
  - Algorithms, design and analysis. Part I
  - Computer Architecture
  - Calculus : single variable
  - pre-calculus
  - introduction to logic
  - introduction to computer networks

Re: The software development final exam: Algorithms and Data Structures

#89

Post by minikomi » Mon, Oct 08, 2012, 1:09 PM UTC

I'm self taught and I'm in two minds about this. In one way, these are fundamental questions and, yeah, we should at least know why they're important. However, I can't help feel the binary nature of the questions is a bit like asking a Computer Scientist "Which flag do you set on an Android Intent to make sure an activity only exists at the top of a history stack?" straight off the bat... It favors those who have prepared specifically for the question.

In any case, I guess I have a bit of reading to do..

Re: The software development final exam: Algorithms and Data Structures

#90

Post by LaRakel » Mon, Oct 08, 2012, 1:09 PM UTC

pjmlp wrote: post #34

plinkplonk wrote: post #14

This is the interesting bit "on each paper, at least four of the five questions relates directly to material I have needed to know during my time working on Tarsnap, " Most software jobs are far more distant from CS that Colin's. And more power to him for working fulltime on something that leverages his knowledge. (spoken as someone who spent a decade doing glue-random-apis-together-and-bill -by-the-hour enterprise s…

Yet, at least in the European countries I've lived in, you won't get through HR without a CS degree, unless you're doing your own business.

That's patent nonsense in Belgium as well, true some companies do care. But I've often seen the opposite, they don't care at all what degree you have. They care if you can pass _their_ test. Because obviously they're better at testing people than colleges are.