Google Data Center Automation Software Engineer interview questions

Applied for positions on Google Job site I seemed qualified for. After a few weeks received email from recruiter asking if I was interested in phone interview. Phone interviewer was nice but really was not interested in background or general knowledge just wanted to work the technical question in Google docs. I did not recognize the problem as recursive and told the interviewer I would start out with a simple inefficient solution and try to think of a better solution as I progress. I was very nervous and can't really think clear in such situations. Anyway interviewer gave me hint solution was recursive so reworked function and created a recursive version. Then was asked to provide test variations which I seemed to think of pretty well and was told that I provided all the one the interviewer could think of.