eBay Software Developer interview questions

They come to campus. My interview is 9 am in the morning, and they were late. This made me mad. Without given a job description, they start the interview. I have around 4 year work experience, they ask me some binary operation.

Attended a job fair and had dropped my resume. They called me in a week for an interview session. Asked me to implement Sudoku. Asked me several data structure questions. Asked me the difference between abstract class and interface. A brain teaser: I have 25 horses and I want to find the fastest amongst them. The contraint is that I do not have any time measuring device. I am given a circular racecourse wherein a max of 5 horses can run in parallel at a given instance of time. How will you find the fastest one.