Software engineer ruby on rails Interview Questions | Glassdoor

Software engineer ruby on rails Interview Questions


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Describe a routine which returns the set of integers in {1..100} divisible without remainder by 3 but not by 9.

12 Answers

I'm assuming the question wants us to find integers that are divisible by 3 but not by 9. This can be easily obtained using a mod function inside the following if statement: if(number % 3 == 0 && number % 9 != 0) Here is a short program I wrote in c++ to show how to solve this problem. Instead of returning the set of integer, I just printed them out on the screen: #include #include using namespace std; int main(int argc, char** argv) { int i = 0; vector list; vector::iterator it; for(i = 1; i <= 100; i++) { if(i%3 == 0 && i%9 != 0) { list.push_back(i); } } for(it = list.begin(); it != list.end(); it++) { cout << *it << endl; } return 0; } If I missed anything, please let me know. Happy coding and problem solving!

That'll certainly work, Tyler, but the OP indicated he was interviewing for a Ruby On Rails - not C++ - gig.

put those integers into an array, pick every third element, out of which discard every third element.

This was a pair programming session with a Ruby engineer. They allow you to use your own laptop which was great but you only get 30 minutes to finish the problem with working unit tests. I think they re-use this pair programming problem so I'm not going to divulge details here. But it wasn't a particularly hard problem, they just want you to see how you code and test. Do not forget to write unit tests! Ideally you would develop it in a TDD fashion.

2 Answers

How would you optimize Ruby for performance?

1 Answer

If we have 8 same little balls, but one of them is less weight. How may times do we need to weigh them to define which ball is less weight?

2 Answers

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Am I equally comfortable with the front-end of the Rails stack as I am with the backend?

1 Answer

How did you become a Ruby on Rails Developer?

1 Answer

HR Interview

1 Answer

What do you like to do at your spare time with regards to software?

1 Answer

Most difficult was probably a moderately complicated SQL query.. at the time I had been doing lots of rails and my head was not in the pure SQL mode at all. It was my fault for not brushing up on that before coming in, but I did my best and talked it out as I wrote it. I got the entirety of the idea correct and the majority of the syntax correct, but some of it was a little railsified out of lack of wholly memorized SQL syntax.

1 Answer