How do I implement LFU and LRU caching algorithms?

How do I implement LFU and LRU caching algorithms?

To implement LFU (Least Frequently Used) and LRU (Least Recently Used) caching algorithms, you can use data structures like hash maps and linked lists. Would you like a code example?

Yes, please provide a code example for both algorithms.

Sure! For LRU, you can use an OrderedDict in Python. For LFU, you might need a combination of a hash map and a min-heap. Would you like to see the code for LRU first?

Yes, let's start with the LRU implementation.

Here's a simple LRU cache implementation in Python using OrderedDict:

from collections import OrderedDict

class LRUCache:
    def __init__(self, capacity: int):
        self.cache = OrderedDict()
        self.capacity = capacity

    def get(self, key: int) -> int:
        if key not in self.cache:
            return -1
        else:
            self.cache.move_to_end(key)
            return self.cache[key]

    def put(self, key: int, value: int) -> None:
        if key in self.cache:
            self.cache.move_to_end(key)
        self.cache[key] = value
        if len(self.cache) > self.capacity:
            self.cache.popitem(last=False)