Explain iOS ARC and avoid retain cycles
Company: LinkedIn
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Technical Screen
## iOS Memory Management (ARC)
You have 10 minutes to explain iOS memory management under ARC.
Cover the following:
1. **How ARC manages object lifetime** (what it does at compile time, when deallocation happens).
2. The meaning and typical use cases of **strong / weak / unowned** references.
3. **Retain cycles**:
- Common places they occur (e.g., closures/blocks, delegate patterns, timers, notification observers).
- How to prevent and break cycles.
4. What an **autorelease pool** is and when you might need `@autoreleasepool { ... }`.
5. How you would **debug memory issues** (leaks, unexpectedly retained objects) using Xcode tools.
Assume Swift + UIKit/SwiftUI context unless you state otherwise.
Overview: This question evaluates a candidate's understanding of iOS memory management under ARC, covering compile-time reference counting, ownership qualifiers (strong/weak/unowned), common retain-cycle sources and mitigation, autorelease pools, and use of Xcode memory-debugging tools.