Amazon Non Software Development Engineer interview questions

I submitted my resume in a school job fair and got reject. But, HR man emailed me to invite the final on-site interview. In the interview, I met 2 teammates and got one task each. While solving the task, we needed to meet 4 interviews to talk about the task I was doing. To solve my question, I need to use Map. I got rejected from the interview. I think my way to use Map is not good as other members.