Pretty easy, just a take home test about data structures and runtimes. They sent an email to me in order to do this, gave me a lot of time to complete it as well.
I applied through university. I interviewed at Change Healthcare
Interview
Initially, they mail the student and ask for the availability. Before the interview, they let you wait in the reception with a guest identification. The interview is around 30 to 40 minutes. They ask about your experiences with self-projects and previous co-ops. They give a tour of their office and explain the work environments after the interview.
Interview questions [1]
Question 1
What are thread and process and the difference between them? What do you know about deadlock? How can you prevent them? Any knowledge about Dicom or PACS system?