Bloomberg Senior Developer interview questions

Worst interview processes. I applied for the post of senior software developer through LinkedIn. I got a mail for telephonic interview. In telephonic interview, he asked me to traverse a binary tree vertically. I answered it correctly. The interviewer was all satisfied. After 2 days, I got rejection mail. I don’t know on what ground they rejected me. The only thing I can think of is I needed a visa sponsorship. If you can’t provide visa sponsorship then don’t initiate interview process

It took around 1 week and recruiter sent an email for a 30 mins call. The recruiter was kind of rude and not friendly. And I had a group interview with 3 persons 1 week later. And received a thank you email in the next day.