DE Shaw QR phone interview

I have the first phone interview for quant research internship coming up. What are some common kinds of questions they like to ask for this round? Should I prepare for very technical questions?

I got 3 questions: the minimum number of comparisons to find the max of an array & prove the optimality, how does t-statistic change if you double the size of data set and a question on momentum trading (the interviewer told me about the concept before asking questions)