First, I received a short call from Bloomberg HR after being referred by a friend. We mainly talked about some simple behavioral questions and I was asked to choose between the Houston or NYC office. The HR representative then helped me schedule a 30-minute phone interview with a Bloomberg engineer one week later. The technical interviewer was friendly and talked a lot during the interview process.

Easy problem: given a string of numbers, add a comma (",") between every thousand.

For example, given "1000000", get "1,000,000."

Even though the problem is easy, the interviewer asked a lot of questions about the time complexity, especially concerning substring operations and string concatenation. Waiting for my onsite interview.