First round was a 30 minute call. First half was behavioral, asking about previous experience both professionally and org-wise, second half was technical, asking questions about C++ structure and memory management. Second round is an open note OA for one problem. I was given 24 hours from start, but question I received was luckily easy compared to others. Third round is completing a word doc describing your education status and then your four largest accomplishments in bullet-point form (1-2 sentences for each accomplishment).