I had my first-round interview at school. The interviewer was very nice and began with a short introduction about DE Shaw and his role there. He then asked a simple coding and algorithmic question: implementing a merge iterator in C++. After I finished coding, he asked a few questions about the complexity of the algorithm and how to improve it using a priority queue. I received an invitation for the on-site interview that same evening. Before attending, I needed to submit a sample of my code (approximately 300 lines) for review.

I traveled to New York for the second round. The hotel and restaurant accommodations were very pleasant. I had three technical interviews in the morning, which went quite well. Following these, they scheduled an additional technical interview with a senior VP for the afternoon. He also posed several interesting technical questions, such as:

• Given a method foo(int a[4]), write code to call foo with a initialized to [0,0,0,0], [0,0,0,1], [0,0,0,2], [0,0,1,0], and so on, up to [2,2,2,2].
• Given two classes of shapes (Rectangle, Circle) that inherit from Shape, and two classes of printers (BW, Color) that inherit from Printer. Also given four methods:
  • PrintRecBW(Rectangle s, BW p)
  • PrintRecCol(Rectangle s, Col p)
  • PrintCirBW(Circle s, BW p)
  • PrintCirCol(Circle s, Col p) Write a method Print(Shape s, Printer p) to print (s, p) using the four methods above WITHOUT using if. You are allowed to implement additional methods in the given classes.

I felt I performed well in this interview as well. Finally, they scheduled an interview with the manager of the team. He asked me some general questions about my research and work experience, followed by some obscure technical questions with no definitive right or wrong answers, for example:

• Do we need the Integer class in Java? Why?

I believe I did reasonably well in this final interview, with the exception of the Integer class question.

Why do you want to switch from research to industry?