I applied online. I interviewed at Citadel Securities
Interview
Initial phone interview - generic DSA.
Next round was an onsite. First 2 hours were OK, another DSA and the other explored C++ knowledge and some brain teasers. After 2 hours there was an hour lunch, which I had by myself in a conference room. Kind gentlemen brought in a nice assortment of food, but I was left to sit and ponder for an entire hour, alone, and with no idea if someone would come and chat / have lunch with me,
3 hours in, and another engineer comes in for a round to explore testing. He was super unprofessional: ignores questions while on phone, yelled and swore at the laptop we were using due to something not working.. Those final two hours left a very bad impression.
A fifth hour was also scheduled, but not used due to the person being too bust or not in (wasn't clear, third guy just said either or). Waited 10 minutes for a random person to come in and say the 'interview is over now, you can go'. Got my things and left the building without saying bye to anyone...
Interview questions [3]
Question 1
Design a random generator given a list of probabilities
I applied through a recruiter. I interviewed at Citadel Securities (New York, NY)
Interview
The process was quite standard, but there was a big time gap between the OA and the interview. All rounds had both a background discussion and technicals. Technical rounds were with actual SWEs. They were pretty friendly, and more concerned with problem-solving than trivia or language depth.
Interview questions [1]
Question 1
OA was quite easy, 2 questions: first was lc medium, second was lc easy. First round was standard DSA question for an order book string problem. Second round was heavy C++ debugging.
I was reached by a recruiter, and I was later called for a personal interview which happened on zoom. This was for HK location. There was no online assessment test.
Interview questions [1]
Question 1
Implement queue using vector, no constraints were given. I did it but took some time - verdict - reject.
Also asked in depth about a project I've worked on and I am proud of. I spoke of the last project I had worked on, he seemed satisfied didn't ask a lot of cross questions.
Standard frontend exercise. Know your javascript and react. Be prepared to explain how you would optimize for performance.
Explain in depth how react renders and rerenders.
Handle real time data display.