LRU Cache

Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. Implement the `LRUCache` class: - `LRUCache(capacity)` Initialize the LRU cache with positive size capacity. - `int get(key)` Return the value of the key if it exists, otherwise return -1. - `void put(key, value)` Update the value of the key if it exists. Otherwise, add the key-value pair to the cache. If the capacity is exceeded, evict the least recently used key.