Bloomberg does a technical interview for round 1, so that's what I've experienced. It was hosted on HackerRank, which also provides an audio and video conference, and it was ~1 hour long: 10 minutes going over my resume, 40 minutes for the coding challenge, and 10 minutes for me asking questions.
--------10 min resume review--------
This was a stress-free part, since you'll be telling stories about the things behind your resume. If you've listed any projects, be prepared to talk about what language you used, what data structure you've implemented, etc.
--------40 minute coding challenge--------
My coding challenge was to implement the game Zuma. The nature of the challenge revolved around string (or vector) manipulation and recursion.
I didn't have enough time to finish implementing the whole thing, but I was mostly there (~87% was my guess). I wrote pseudo code and talked with my interviewer on how I would finish my implementation.
All the details of this part will be in the Interview Questions / Answers section of this review.
--------10 min me asking questions--------
I prepared a few questions for this last part to get a feel of how working at Bloomberg was like. I've forgotten about the whole pandemic situation, and so when I asked my interviewer about recent challenges, one thing he mentioned was that it's more difficult communicating with the team when they're not in person.
He also talked about how design choices are another big challenge. I always thought that the most difficult thing as a software developer is the actual coding of a difficult feature. But, my interviewer talked about how a dev team can have disagreements on how to implement a typical feature, which happens well before the actual coding.
When I asked about any hobbies that people at Bloomberg have, he mentioned that gaming has been on the rise (heh) due to everyone staying at home. I thought that was neat.
--------RESULTS--------
I got word back from Bloomberg ~1.5 weeks after this interview (this first round was right before July 4, so everyone was in holiday mode), and I'll be doing my second round of interviews on the last week of July 2020.