Microsoft Software Engineer interview questions

The first interview in microsoft. It was a cool but difficult Interview. The interviewer asked me to tell him about some project I completed in university. He have also asked basic questions such as "what is polymorphism?", "what is heritance?", and so on. Then the interview actually started. He asked me about binary tree serialization, including code writing. He left me a couple of minutes alone in room and then checked my code with me. He also asked me to sketch on the board what I did. Then asked me one more little question about "SetAll" in O(1), It was an easy (and tricky) question but didn't know the solution, so he tried to help me but I failed. After 90 minutes the interview was ended.