Design a HashMap + Apply Builder/Factory Patterns

Problem

Implement a HashMap from scratch (buckets, resize, collision handling), then use Builder/Factory patterns to construct configurable objects.

Requirements

• put/get/remove, load-factor resize, chaining or open addressing
• Builder for a complex config object
• Factory for creating handlers by type

What evaluators look for

• Correct collision handling and resize
• Clean, intention-revealing pattern usage
• When NOT to use a pattern (over-engineering)

Extension

Discuss the inner workings of HashMap (hashing, buckets, treeify).