Interview Question for Contract Ruby On Rails Software Engineer at LinkedIn:

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 <vector>
#include <iostream>
using namespace std;

int main(int argc, char** argv)
{
   int i = 0;
   vector<int> list;
   vector<int>::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.

python
[x for x in range(0,100) if x % 3 == 0 and x % 9 != 0]