ByteDance Software Development Engineer Interview Experience and Insights

First Round: A 40-minute in-depth discussion of my internship and project experience, interspersed with standard interview questions on computer networks, operating systems, Redis, and MySQL. System d

First Round: A 40-minute in-depth discussion of my internship and project experience, interspersed with standard interview questions on computer networks, operating systems, Redis, and MySQL. System design questions included how to design a short-connection system (solving hashing problems) and how to perform hot migration from MySQL to a heterogeneous database (synchronous dual-write + canary rollout). The last 10 minutes were spent on a coding challenge: LC 322 Coin Change, a classic complete knapsack problem, paying attention to the traversal order (combinations, not permutations). The standard interview questions were quite in-depth, similar to the style of interviews in China. A second round was scheduled for the following day. Second Round: A brief discussion of my internship experience and standard interview questions, covering key points and difficulties, lasting about 20 minutes. Then came the coding challenge. The first question was about the number of digits that do not contain consecutive 6s, given an n-digit positive integer. For example, if n=2, only 66 out of 0-99 does not meet the requirement, so the output should be 100-1=99. This could be solved using dynamic programming, taking about 10 minutes. The second question involved a log file containing a triplet of '[uid, login_time, logout_time]', representing the login and logout logs for a specific software on a given day. The task was to output all local maximums. The solution involved creating a difference array, converting the input timestamps to Unix timestamps and recording the differences, then using the difference array to reconstruct the original array and find all local maximums. This took approximately 30 minutes. The day after the interview, I received an email stating that the position had been filled. Although I ultimately failed, the entire interview was conducted in Chinese, which was a positive experience. I suspect I failed on the log question, perhaps because they were hoping for a more efficient event-driven scanline approach.