Implement a dictionary without built-in Dictionary

Implement a key-value map type (a “dictionary” / hash map) from scratch, without using the language’s built-in dictionary/map as the underlying storage.

Requirements

• Support at least:
  • put(key, value)
  • get(key) -> value | null
  • remove(key)
• Keys are hashable.
• Handle hash collisions correctly.
• Discuss or implement resizing/rehashing to keep operations efficient.

Constraints / Goals

• Aim for O(1) average time per operation.
• You may use arrays/lists as the underlying storage, but not a built-in associative container.

Follow-ups

• Compare separate chaining vs open addressing.
• How would you design this as a generic type (e.g., in Swift: Key: Hashable )?