Context

At companies like Spotify or Stripe, data processing tasks often require choosing the right algorithm for filtering, grouping, ranking, deduplication, and dependency analysis. Interviewers want to know whether you can identify the algorithmic building blocks behind these operations.

Core Question

What algorithms do you consider essential for data processing? In your answer:

1. Explain which algorithm families are most important and what problems they solve.
2. Compare when you would use sorting, hashing, heap-based methods, and graph traversal.
3. Discuss the main time/space tradeoffs and common implementation pitfalls.

Scope Guidance

You do not need to list every algorithm in computer science. Focus on the practical core set that appears repeatedly in real data workflows, explain why each matters, and show that you can choose the right tool based on input size, ordering requirements, memory limits, and whether the task is batch or incremental.