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`)?