Microsoft Software Development Engineer interview questions

I submitted my resume at a career fair at my school for a summer internship at Microsoft and was later contacted for a 30 min on-campus interview. I was asked to solve problems on arrays and to talk about my accomplishments listed on my resume. A month later, I was invited for an on-site interview in Seattle. There were three technical interviews so it involved preparing a lot and practicing algorithms. I was asked questions on binary trees, linked lists and arrays. The recruiters were friendly, the interviewers were not intimidating but I was very nervous. Two weeks later I received an email saying that I was not going to be offered a job. The questions were not difficult but I'd say I needed more practice and to make use of better resources.