1. First step is a take home test. The question consists of a discrete probability generator. Production level code quality along with unit tests are expected.
2. Second rowun consists of a 30 minute phone screen based on your solution. Discussion of edge cases and cases which one could have possibly missed out.
3. The third round is a 90 minute peer coding interview of a question which involves re-arranging stock market data. This is a two part question. Since it's a toy example, be aware that your data structure would be simple and don't try to optimise for the second part.
4. Forth round is a 60 minute algo/ds round with a simple warm-up question followed by a graph search problem.
Overall, an easy interview compared to what's out there these days, just wish that round 3. would be better, since the toy example makes one focus on aggregation which changes the data structure making part 2 of the question odd.