This time it is Bloomberg complete process of 26NG SDE, from phone call to offer, takes about a month. The overall pace is very fast and every round is very solid. The interview style focuses on engineering skills + communication and expression + distributed system basics. There are no particularly tricky brain teasers, but the depth is not low.
Timeline reference
10.9 Phone Screen
10.29 VO1 + VO2 + HR
11.4 EM
11.6 HR offer call
Basically, it progresses quickly after each round, and the feedback efficiency is very high.
Phone Screen
The phone aspect is overall more basic. Behavioral questions include Why Bloomberg and talking about one of the most challenging projects. The digging is not particularly ruthless, but the details will be asked. There are two coding questions, one is LC easy, given a social graph, find the first partner that meets the conditions, which is essentially graph traversal plus conditional screening; the other is LC 2062, counting the substrings that meet the conditions. The difficulty is not high, it mainly depends on whether the code is stable and whether the boundaries are clearly considered.
VO1
VO1 starts with a noticeable increase in intensity. I still introduce myself first, then dig into the project and ask more detailed questions, such as design decisions, trade-offs encountered, and how to solve performance bottlenecks.
The algorithm question is a modeling question. The scenario is that there are many TV dramas, each drama has 10 episodes, and users will be lost every time one episode is broadcast. To find the nth episode such that after this episode, 70% of users can still watch all 10 episodes. It is essentially a probability simulation problem. It is necessary to know how the retention ratio accumulates after each episode and how to model user churn.
Follow-up is very typical, testing boundaries and abstraction capabilities. For example, what if all users are lost in the first episode? What if all users could watch all 10 episodes? Another issue is code optimization, which requires you to change an if statement to a way of writing that does not require explicit logical judgment. What is tested is your understanding of expressions and structures, not syntax.
The conversation was very natural in this round, and I left 10 minutes for counter-questions at the end. I asked a lot of questions about wlb and commuting. The interviewer also chatted very sincerely and made an appointment for the next round on the spot.
VO2
The question is: There is a Tesla Equity, the trader can update the daily price or delete the latest price; the analyst can obtain the latest price, maximum price and average price, all operations must be O(1).
The essence of this question is a data structure that supports push / pop / getLatest / getMax / getAverage. The conventional approach is to use a stack to store the price, use an auxiliary stack to store the current maximum value, and use a variable to maintain the prefix sum, so that the average value can be calculated in O(1).
But the bonus point for this question is not in the algorithm, but in OOD. It is recommended to abstract equity, trader, and analyst into classes and separate the responsibilities clearly. For example, equity is responsible for storage and state maintenance, trader is responsible for modification, and analyst is responsible for query. The interviewer obviously prefers this structured expression rather than stacking all logic in one class.
Follow-up is a dictation of LC 295 (data flow median). It only needs to talk about the dual-stack idea and does not require implementation. It mainly depends on whether you can clearly explain why it is designed this way.
This round also left time for rhetorical questions. We talked about what the team does specifically, what the technology stack is, and what the atmosphere is like. We also made an appointment with the EM on the spot.
HR face
This round is basically a collection of behavioral questions. I asked about an experience when I had a disagreement with a teammate, about an experience when I learned something new from scratch, why CS, Why Bloomberg, and another about something that was not written on my resume. The overall rhythm is relatively relaxed, but the answer must be structured and not scattered.
HR finally said to push it to EM, but it couldn't be scheduled that day.
EM side
The EM side is the hardest in the entire field. The focus is System Design, requiring the design of Kafka.
The interviewer starts from the most basic components, including the concepts of producer, consumer, topics, partitions, and brokers, all of which must be explained clearly. Then I asked you how to provide the ability to send messages to producers. My idea at the time was to encapsulate the retry mechanism and messages into an SDK and provide a unified interface to the outside world.
Then ask how Durability, Consistency, and Availability are guaranteed. This is the basis of distributed systems. For example, you must be able to talk about replication, ack mechanism, leader-follower architecture, data flushing strategy, etc.
There was one question that I didn't answer well at the time. The scenario is that producer1 sends a message to broker1. Producer2 originally planned to send a message to broker2, but due to network problems, it was sent to broker1. How to ensure the message order at this time? I didn't think clearly at the time. The general idea given by EM is to select a leader based on raft. The leader determines the order of messages, and other brokers can follow the order of the leader. The core is that the order must be adjudicated by a central authority.
Interview results
The overall feeling is that the Bloomberg interview is not flashy, but very real. The difficulty of the algorithm is medium to high, the data structure design is more engineering-minded, and the EM wheel has high requirements for distributed distribution. If you have a solid foundation and stable expression, it is actually a very fair process. Finally, I received the HR Offer call two days later, and the process ended relatively smoothly. Need to sort out high-frequency questions from Bloomberg / Dachang VO / EM, or want to be more targeted VO assists you can find programhelp, which is very familiar with the entire SDE process of major manufacturers.
