I was doing my Master's in Singapore. I applied through Microsoft's University Recruitment page in November. I was contacted for an initial phone screen, which was pretty basic. It included a basic profile review plus a question to test my viability for an SDET role (How will you test a keyboard?).

After around 15 days, I was confirmed for an onsite interview to be held in February. The interview consisted of four 1-hour rounds of one-to-one interviewing, with a 15-minute HR briefing in between each interview. Questions were mostly on algorithms, data structures, and other concepts (such as recursion, client-server architecture, etc.).

After three rounds, all the interviewers met and decided whether or not to proceed to a fourth round. They might reject you then and there, or might accept you if you have been very good, or in about 50% of cases, go for another round.

I was called for a fourth round and was given an offer within 10 minutes of its completion.

How do you find the lowest common ancestor in a binary tree (not a BST)?