I interviewed for a position with the Workday Next team. I had two interviews. The first interview was a technical phone screen. Basic understanding of data structures will get you through this part. I would not expect anything more challenging than binary trees. For each problem, you were also asked to write your I/O handling and test cases. The second interview was a 45 minute behavioral phone interview. This was more difficult than the technical phone screen. My interviewer emphasized that cultural fit is very important for Workday, so I would try to study Workday's values and make sure you are able to speak to them in your answers.