LRU cache is an algorithm used for page replacement by memory management systems. The LRU cache is an acronym for the Least recently used cache. It replaces any page that is not used for long and is replaced by the most recently used page whenever the memory is full. The queues and hash maps are used to implement the LRU cache. A queue is an implementation of a doubly linked list. The cache size, i.e., the total number of available frames, determines the maximum size of the queue. The least recently used pages will be near the front of the queue, while the most recently used pages will be near the back.