LFU Cache Design

Design a LFU Cache and implement the following operations: get(key) - Retrieve the value associated with the key if it exists, otherwise return -1. put(key, value) - Update the value of the key if it exists. If it does not exist, insert the key-value pair. When the cache reaches its capacity, it should remove the least frequently used entry before inserting a new one. The operations should follow the LFU (Least Frequently Used) strategy. Example Input 2 put 1 1 put 2 2 get 1 put 3 3 get 2 get 3 put 4 4 get 1 get 3 get 4