Data Analyst

How do you aggregate values by a single field and metric in Pandas?

If you give a coding agent access to the internet — what do you lose?

D. Valera and vending machines In a business center, there are 10 externally identical vending machines with chocolates. Each machine dispenses a chocolate with its own fixed probability, which is initially unknown and may differ between machines. Sweet-tooth Valera wants to get as many chocolates as possible, but his budget is limited to 200 tugrik. Each purchase attempt (using any machine once) costs exactly 1 tugrik — payment is made regardless of whether the machine dispenses a chocolate or not. Valera, trying to learn the probabilities of the machines, met security guard Alexei, who shared an important piece of information. The guard told him that 2/5 of the machines have probabilities drawn from a uniform distribution on [0.2, 0.3], 2/5 from [0.4, 0.5], and the rest from [0.85, 1]. Your task is to devise an algorithm that helps Valera get as many chocolates as possible. Interaction protocol This is an interactive task. Your program should first output the number of the machine — a number from 0 to 9. Then the system (interactor) will return the result: 1 if a chocolate was dispensed, or 0 if not. Your program can read this value (for example, via input()) to use in further calculations. Scoring system In each test, the percentage of successful attempts to get chocolates will be evaluated. If this percentage exceeds 75%, the test is considered passed. Note It is recommended to use Python 3.8 (Handbook DS) as the compiler.

Intern

Яндекс

What to do if you need to break backward compatibility (for example, by adding a mandatory field)?

Middle

СБЕР

Why did you decide that nothing suits you on this position so quickly, in 7 months?

Two prisoners in different cells flip coins and, seeing only their own coin result, must guess the result of their neighbor's coin. If at least one guesses correctly, both are released; if both are wrong, they are killed. What strategy should they choose to survive with 100% certainty?

Middle

МТС

What experience do you have with channel encryption (TLS, MTLS)? How did you verify authorship and data integrity?

Middle

СБЕР

SQL: write a query to count the number of subscribers for each blogger (table with bloggers and subscribers).

Intern

Т-Банк

What indicators do you think a sales director should see daily on dashboards?

What are your weaknesses and strengths?

What can and cannot be done when designing an API to maintain backward compatibility?

Middle

СБЕР

How do you understand that the formulated technical task (TOR) is complete and ready for transfer to development? What are your criteria for readiness?

What is a foreign key and how does it differ from a primary key?

Have you worked with window functions? Which ones do you know?

Intern

Альфа-Банк

How does the WHERE operator differ from the HAVING operator?

Intern

Альфа-Банк

SQL task: calculate conversion by experiment groups (exp_id=90) from Epic Match Start event to Epic Fight Win based on users, with correct event attribution to the experiment via join on time.

What do you think about Apache Superset as a tool?

Tell me about the logic of calculating Report 2: the attributes 'Already approved above' and 'Approved' — what do they mean and how are they calculated?

Do you have a habit of studying something additionally, reading, or following someone in your professional field?

Have you had experience optimizing SQL queries, and how did you do it?