LeetCode #146 - LRU Cache: Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get(key) and put(key, value). The order of the keys and the constraints on memory usage are crucial.

``` class LRUCache:\n def __init__(self, capacity: int):\n # Initialize the cache and its capacity\n def get(self, key: int) -> int:\n # Return the value of the key if the key exists in the cache, otherwise return -1\n def put(self, key: int, value: int) -> None:\n # Update the value or insert the key-value pair if not already present ```