Build a Least-Recently-Used Store

Implement an in-memory key-value store with least-recently-used eviction. The store is initialized with a positive integer `capacity` and supports two operations: - `get(key)`: Return the value associated with `key` if it exists; otherwise return `-1`. Accessing a key makes it the most recently used key. - `put(key, value)`: Insert or update `key` with `value`. Updating an existing key also makes it the most recently used key. If inserting a new key causes the number of keys to exceed `capacity`, evict the least recently used key. For this interview variant, you do not need to use a linked list. An implementation based on a hash map plus a dynamic array/list is acceptable, even if moving keys in the list costs linear time. Example: ```text store = Store(capacity = 2) put(1, 10) put(2, 20) get(1) -> 10 # key 1 becomes most recently used put(3, 30) # evicts key 2 get(2) -> -1 get(3) -> 30 put(1, 15) # updates key 1 and makes it most recently used get(1) -> 15 ```