The first part was less of an interview and more of a test. I was given a sheet with several algorithmic questions and was asked to answer them alone in a room. Every now and then, the interviewer came in, asked if I had any questions, and I explained the solutions I had so far. Sometimes he asked for additional questions to understand what I tried. The questions were pretty hard. The second part was similar, but with fewer and easier questions. This time I had a longer conversation with the interviewers and discussed each problem thoroughly. After I received the offer, I was invited again to the office for a long explanation about what the company does in order to interest me more, but eventually, I had another offer I preferred better.

Regular phone call screening. Nice interviewer, gave feedback during call. Asked questions in probability and in algorithms & complexity. Phone call lasted about 45 minutes. I didn't do my homework, and wasn't prepared for the interview. A revision of probability brain teasers and puzzles is recommended (dice, coins, basic sorting algorithms ets).