My initial communication was also my last communication. I talked with the HR representative on the phone. She was very pleasant and said that judging by my resume, I would be a good fit for the position.

At the end of the conversation, she said that she would email a 'coding challenge' that should take no more than 4 hours to complete. I got it and finished it within the time constraints, mailed it back and then heard nothing, not even a 'thank you we're not interested'.

It seems that Glassdoor will not allow me to post the entire question, but I can summarize by saying that you need to find the position of a string of up to 20 characters [A - Z] without generating all possible permutations.

It has to run in less than 1 second, so an O(n) solution is preferable.