Microsoft visited our campus, and I submitted my resume. An on-campus interview was originally scheduled, but it was canceled due to Hurricane Sandy. Consequently, they arranged a phone interview. The phone interview wasn't difficult. I was asked to compare two binary trees to determine if they were identical and to design a vending machine.

After two weeks, I received an email regarding further steps. It seemed Microsoft had a long candidate line, so I was scheduled for an on-site interview in January. Candidates gathered in the lobby of Building 111, and recruiters met with us one by one. We were then given information about our interviewers and shuttles to take us to different buildings.

The interviewers were pleasant and tried to be inspiring, assisting me with the technical questions. I was somewhat unsatisfied with the later stages of the interview process. After the fourth interviewer, I was sent to a fifth interviewer and was told I needed to wait for an hour. After waiting in the lobby for 45 minutes, the interviewer arrived and informed me that my day was over. I didn't expect to receive an offer from Microsoft, but making candidates wait and then dismissing them is certainly unprofessional.

1. Write a singleton class and make it thread-safe.
2. Merge two sorted arrays.
3. Remove duplicates in an array.
4. Did you ever write any code just for fun?