I applied online and got an email from a recruiter for scheduling a phone interview. The telephonic interview was not very hard, basic C and C++ concepts like
1) The difference between struct, union and class
2) malloc vs new
3) what does malloc return when it cannot allocate memory?
After a week or so, I was asked to come to their NYC office for an onsite interview. Bloomberg has interview days and on every such day they have around 18-25 candidates for interviews. My interview panel consisted of 3 members, 1 was a shadow interviewer and other 2 were the one's who were actually doing the interviewing.
The interview was not very hard. I had a coding question on string reversal. Another one was on data structures and you should absolutely know which data structure is to be used in what situation along with the complexities for each of the operations. If you don't, then you have slim chances of answering such questions. My last question was the hardest one and required databases and multithreading combined together to form the solution. The interviewer had sort of mugged that question and had come for the interview. When I asked her to explain a little bit more, she kept on saying the same things again and again. Finally, the other interviewer had to intercept, reinterpret that question, confirm his understanding with the other interviewer and then had to explain it again to me.
Overall, it was a very bad experience. The culture is not very good and you can actually sense it from the interviewers' attitude. One of my interviewers was all the time texting on his cellphone when I was given a chance to ask them questions. That was pretty rude.
Warning - Check out the culture from someone inside that you know before you join!