LRU Cache

Implement the LRU (Least Recently Used) cache mechanism. You need to support get and put operations. get(key) - Get the value (always positive) of the key if the key exists in the cache, otherwise return -1. put(key, value) - Set or insert the value if the key is not already present. When the cache reaches its capacity, it should invalidate the least recently used item before inserting a new item. Please construct a class to fulfill the functionality above, initialize the cache with a positive integer as capacity. Example LRUCache cache = new LRUCache(2); cache.put(1, 1); cache.put(2, 2); cache.get(1); // returns 1 cache.put(3, 3); // evicts key 2 cache.get(2); // returns -1 (not found) cache.put(4, 4); // evicts key 1 cache.get(1); // returns -1 (not found) cache.get(3); // returns 3 cache.get(4); // returns 4 Constraints 1 <= capacity <= 3000 0 <= key <= 10000 0 <= value <= 10000 Up to 3 * 10^4 calls will be made to get and put Example Input 2 put 1 1 put 2 2 get 1 put 3 3 get 2 put 4 4 get 1 get 3 get 4