Explain iOS ARC and avoid retain cycles

iOS Memory Management (ARC)

You get 10 minutes to walk through how iOS memory management works under ARC. Address these points:

1. How ARC controls object lifetime (the compile-time work it performs and when objects are deallocated).
2. What strong / weak / unowned references mean and where each is normally used.
3. Retain cycles:
   • Typical sources (for example closures/blocks, delegate patterns, timers, notification observers).
   • Ways to avoid them and break existing cycles.
4. What an autorelease pool is, and the situations where @autoreleasepool {... } becomes necessary.
5. How you would use Xcode tools to debug memory problems such as leaks or objects that stay alive too long. Assume a Swift + UIKit/SwiftUI setting unless you say otherwise.

Overview: The question tests how well a candidate understands iOS memory management under ARC: compile-time reference counting, the strong/weak/unowned ownership qualifiers, frequent retain-cycle causes and how to address them, autorelease pools, and Xcode's memory-debugging tools.