LRU算法实现

LRUCache.py

class LRUCache(object):
    def __init__(self, capacity):
        self.capacity = capacity
        self.queue = []
        self.cache = {}

    def to_dict(self):
        return {"capacity": self.capacity, "queue": self.queue, "cache": self.cache}

    @classmethod
    def from_dict(cls, d):
        ins = cls(d["capacity"])
        ins.queue = d["queue"]
        ins.cache = d["cache"]
        return ins

    def get(self, key):
        key = str(key)
        value = None
        if key in self.cache:
            if key != self.queue[-1]:
                self.queue.remove(key)
                self.queue.append(key)
            value = self.cache[key]
        return value

    def set(self, key, value=str(datetime.now())):
        key = str(key)
        if key in self.cache:
            self.queue.remove(key)
        elif len(self.queue) == self.capacity:
            self.cache.pop(self.queue.pop(0))
        self.queue.append(key)
        self.cache[key] = value

    def keys(self):
        return list(reversed(self.queue))

    def values(self):
        return list(reversed([self.cache[k] for k in self.queue]))

    def __contains__(self, o):
        return o in self.cache