Направления, темы и вопросы из записей интервью. Фильтры ниже сохраняются в ссылке.
79 questions from real interviews
You have subscription transaction history and need to estimate or predict yearly LTV for a cohort. How do you define the target and build a first baseline without leaking the future?
The backend service on Python became slow under load. How would you localize the bottleneck and understand what exactly to optimize?
How can you avoid blocking the system if resource cleanup or fallback script may also fail?
When to choose threads, when individual processes, and how does GIL affect I/O and computation tasks?
When to choose threads, when individual processes, and how does GIL affect I/O and computation tasks?
What is the difference between flows and processes? What is GIL in CPython when synchronization and IPC are needed?
Explain how the hash table in the Python dict is structured and why lookup/insert operations are usually O(1) but sometimes degrade.
How to check the student's code and give a hint without revealing the finished solution?
You need to forecast how long a ship will wait at a port. How would you define the ML target, time granularity and prediction horizon so the result is useful for operations?
Describe how a model moves from notebook research to production training, versioned model storage and serving for an LTV prediction service.
Describe how a model moves from notebook research to production training, versioned model storage and serving for an LTV prediction service.
How much does it take to insert n different strings of length k into a Python set? What happens when hash returns the same value for all objects?
What is the difficulty of adding an item to the beginning and end of the Python list? Why does an append run on average for O(1), but a separate call may require O(n)?
How to deconstruct Python code with lists, object references, cyclic references, and variable default argument values and explain what will remain in memory?
How to count attempts in the retry decorator so that the logs and metrics reflect the real number of calls?
What design is needed for a Python service that processes match events, builds features, and runs an ML model for real-time analytics?
How do async and await work in Python and how does competitive I/O performance differ from parallel computing?
What does await do in asyncio and why is it important for a non-blocking service?
How to choose the delay between repeated requests and why add random variation to it?
There is a legacy C component and a desire to give users a convenient Python/API layer. How to decide: make a wrapper around C or completely rewrite the implementation in Python?
After BM25 baseline you need to strengthen the search for articles. How to design a candidate generator, hybrid retrieval and reranker?
How can a forecasting system support multiple prediction horizons, and what does it mean that SHAP is model-agnostic?
What should a stream job look like for a CTR dashboard: what does it read, what does it count, and where does it write the result for the advertiser’s chart?
If the CTR panel receives millions of events per second, how do you estimate the number of Kafka partitions and Spark handlers and where to look for the bottleneck?