Банк вопросов из реальных собеседований

What are the basic algorithm families in the recommendations and what to do with cold start?

Compare insertion and access complexity for a singly linked list, Python list, Python dict, and string concatenation. Where do amortized O(1) and worst-case caveats matter?

A disease has prevalence 1%. A test is 99% accurate for both sick and healthy people. If the test is positive, what is the probability that the person is actually sick?

How does a tokenizer translate text into identifiers, how do common algorithms differ, and when a new dictionary for a language or domain is needed?

There is a coin with an unknown probability of heads p, 0 < p < 1. How to get a fair random bit 0/1 using flips of this dishonest coin?

You already implemented set/get/sum for an Excel-like table with formulas and cycle checks. How would you add per-cell undo and redo operations?

There is a large TIN stoplist and PDF text where the numbers can be glued together or carried. How to quickly find candidates and not accept part of the account for the counterparty’s TIN?

Connect four different topics: embedding learning, RAG architecture, SHAP explanations, and quantile regression.

Why is dict searching usually faster than list searching, what is a decorator, and when is a generator useful?

What do `_attr` and `__attr` mean in the Python class, and how is convention different from name mangling?

In Python, what actually makes a tuple: parentheses or comma? Give examples.

After computing revenue metrics in Pandas, what simple anomaly checks would you run on the table before trusting the result?

What happens if you assign one list to another variable and change it? What is the difference between shallow copy and deep copy?

What is a Python context manager, what do __enter__ and __exit__ do, and why not just wait for garbage collection?

If several decorators are recorded above the function, in what order do they create the wrappers and in what order are they executed when called?

What do the five principles of SOLID mean, and how do they help you change your server code without being too connected?

Why do pytest need fixtures, how to organize the preparation and cleaning of resources and what areas of action are available?

When to use async, threading and multiprocessing in Python, and how does the GIL influence these choices?

How does @dataclass reduce boilerplate, what does frozen=True do, and how do descriptors or properties relate to attribute access?

What is the Python GIL, when would you use multiprocessing vs multithreading, and how does Python garbage collection work?

What are the differences between asynchronous Lock, Event, and Semaphore, and which server code tasks does each primitive solve?

Explain what the GIL is, why CPython has it, and what happens at a high level when you run a Python file.

Python-service consumes a lot of CPU or memory under load. How to diagnose and what can you do if the problem is really in the Python code?

Explain ROC-AUC for binary classification. When is PR-AUC preferable, and what happens if you compute ROC-AUC on already-binarized predictions?