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> I can clarify tons of math problems for you where the solution is staring you right in the face yet its impossible to solve if you haven't seen it previously.

> I can clarify tons of math problems for you where the solution is staring you right in the face yet its impossible to solve if you haven't seen it previously. Are you seriously contending that Pascal's triangle is such a problem? We all know that "Aha!" problems exist, that there are algorithms that are simple in hindsight despite being anything but obvious before we were told the answer. I don't think anyone here is proposing that such questions are good for interviews. But do you really believe that producing rows of Pascal's triangle, when the triangle has already been explained, is actually one of those "Aha!" questions? If you aren't contending that, I'm not sure what point you're trying to make above.

mbernstein 15y ago
For my solution, after Jemfinch posted about this topic on G+ - I had to remember what Pascal's Triangle essentially was (it's been awhile since I've reviewed the binomial theorem, etc). No big deal. Once one understands the actual problem (wikipedia has a rather nice graphical pyramid showing a few rows being generated), it should be a rather simple task to implement a naive version of it in any modern language. Is my ruby version the best performing? Of course not. However, it demonstrates some obvious insights into it such that the first and last members of a row are always 1's. If I were hiring engineers, I'd be slightly wary if they couldn't at least make basic insights such as that and get darn close within a few minutes. Obviously, there are nerves and other things that can cause issues during an interview process - but one should arrive at a general solution rather quickly, even if it's not the most beautiful. I don't think anyone is trying to be condescending - but the quick naive approach using an array and calculating some sort of offset to get your values is simply bread and butter in our profession.

mbernstein 15y ago

For my solution, after Jemfinch posted about this topic on G+ - I had to remember what Pascal's Triangle essentially was (it's been awhile since I've reviewed the binomial theorem, etc). No big deal. Once one understands the actual problem (wikipedia has a rather nice graphical pyramid showing a few rows being generated), it should be a rather simple task to implement a naive version of it in any modern language. Is my ruby version the best performing? Of course not. However, it demonstrates some obvious insights into it such that the first and last members of a row are always 1's. If I were hiring engineers, I'd be slightly wary if they couldn't at least make basic insights such as that and get darn close within a few minutes. Obviously, there are nerves and other things that can cause issues during an interview process - but one should arrive at a general solution rather quickly, even if it's not the most beautiful. I don't think anyone is trying to be condescending - but the quick naive approach using an array and calculating some sort of offset to get your values is simply bread and butter in our profession.