Amazon Software Engineer I interview questions

My friend helped me submitted my resume, and then I got a call from a recruiter in three days. The recruiter helped me schedule my first round phone interview. My interviewer was a software engineer. In the beginning of the interview, he asked some general questions about my current projects and then moved to technical questions. He asked me to implement a function to print out all the permutations of an input string. I completed it and time was up. In one more week, I got an second round phone interview which is scheduled in next week.