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🎯 Real interview tasks: iOS interview questions

1. Implement parallel image loading without a data race (GCD + async) Senior PRO
2. Implement a debouncer with DispatchWorkItem Middle PRO
3. Implement a thread-safe dictionary (reader-writer) Senior PRO
4. Implement WeakArray<T: AnyObject> Middle PRO
5. Code review: async loading in a UIViewController Middle PRO
6. A table view stutters while scrolling — what do you do? Middle PRO
7. Implement == for a custom Optional Middle PRO
8. any, some or generic: what compiles and what's the difference? Middle PRO
9. Unique numbers from nested arrays, descending Junior PRO
10. Why does memory grow in a loop with UIImage(named:)? Middle PRO
11. Implement a weak-reference collection that conforms to Collection Senior PRO
12. Parallel loading with request deduplication and preserved order Senior PRO
13. Refactoring: find the real leak instead of sprinkling weak self Senior PRO
14. String of 0, 1 and !: minimum error cost Senior PRO
15. k channels: maximize the sum of medians Middle PRO
16. How many segments have max − min ≤ k? Middle PRO
17. A FIFO request queue with type erasure (any / some) Senior PRO
18. Find the bug in this DispatchGroup code Middle PRO
19. Implement map, filter and compactMap for Collection Middle PRO
20. An Atomic @propertyWrapper on os_unfair_lock: what's wrong here? Senior PRO
21. Debounced search on Task: cancellation and stale results Middle PRO
22. Decoding awkward JSON: dates, keys, malformed items Middle PRO
23. Implement an LRU cache with O(1) get and set Senior PRO
24. Memory + disk cache with deduplication: find the bugs Senior PRO
25. One-shot token refresh under concurrent requests Senior PRO
26. A mini network layer: URLRequest → Result<T, APIError> Middle PRO
27. Reverse a singly linked list Junior PRO
28. Parse a string into brand, model and generation Middle PRO
29. A list screen with async loading: state, @MainActor, errors Middle PRO
30. A reused cell shows someone else's image Middle PRO
31. A counter incremented 1000 times from multiple threads: fix it three ways Middle PRO
32. Code review: a completion-based network layer — five interviewer questions Middle PRO
33. Debounce vs Throttle: what's the difference, and implement throttle Middle PRO
34. Reader-writer with a barrier: four interviewer questions Senior PRO