I also did that question. You had access to the full Java docs. I left a nice note explaining how I spent a lot of time trying to do it with the language featu

I also did that question. You had access to the full Java docs. I left a nice note explaining how I spent a lot of time trying to do it with the language feature, but couldn't due to runtime restrictions, and gave them a working non-optimized solution. I was emailed to schedule an interview the next day.