How do I implement LFU caching in my application?

How do I implement LFU caching in my application?

To implement LFU (Least Frequently Used) caching, you can follow these steps: 1. Define a data structure to store your cache items along with their usage frequency. 2. When adding an item, check if it exceeds the cache size. If it does, remove the least frequently used item. 3. Update the frequency count each time an item is accessed. Would you like a code example?

Yes, please provide a code example for LFU caching.

Here's a simple Python implementation of LFU caching using a dictionary and a priority queue:

import heapq

class LFUCache:
    def __init__(self, capacity: int):
        self.capacity = capacity
        self.cache = {}
        self.freq = {}
        self.min_heap = []

    def get(self, key: int) -> int:
        if key not in self.cache:
            return -1
        self.freq[key] += 1
        heapq.heappush(self.min_heap, (self.freq[key], key))
        return self.cache[key]

    def put(self, key: int, value: int) -> None:
        if self.capacity <= 0:
            return
        if key in self.cache:
            self.cache[key] = value
            self.freq[key] += 1
        else:
            if len(self.cache) >= self.capacity:
                while self.min_heap:
                    freq, k = heapq.heappop(self.min_heap)
                    if k in self.cache and self.freq[k] == freq:
                        del self.cache[k]
                        del self.freq[k]
                        break
            self.cache[key] = value
            self.freq[key] = 1
        heapq.heappush(self.min_heap, (self.freq[key], key))

What are the advantages of using LFU caching?

LFU caching is beneficial because it efficiently manages memory by keeping frequently accessed items, reducing cache misses, and improving application performance. It adapts to changing access patterns over time.