【leetcode】146. LRU Cache【H】【9】

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本文介绍了一种使用Python实现的Least Recently Used (LRU) 缓存机制。该机制通过结合字典和列表的数据结构支持get和set操作，并能在缓存满时自动移除最少最近使用的项。

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.

get(key) - Get the value (will always be positive) of the key if the key exists in the cache, otherwise return -1.
set(key, value) - Set or insert the value if the key is not already present. When the cache reached its capacity, it should invalidate the least recently used item before inserting a new item.

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用字典来记录cache的内容

用一个list，模拟队列，来记录使用的顺序

python的 collections是个好动西

class LRUCache(object):

    def __init__(self, capacity):
        self.l = capacity
        self.q = []
        self.dic = {}
        """
        :type capacity: int
        """
        

    def get(self, key):
        if key not in self.q:
            return -1
        else:
            #print key,self.q
            self.q.remove(key)
            res = self.dic.get(key,-1)
        
        self.q += key,
        if len(self.q) > self.l:
            self.q.pop(0)
        return res
        """
        :rtype: int
        """
        

    def set(self, key, value):
        if key in self.q:
            self.q.remove(key)
        self.q += key,
        
        if len(self.q) > self.l:
            self.q.pop(0)
        self.dic[key] = value
        #print self.q,self.dic
        """
        :type key: int
        :type value: int
        :rtype: nothing
        """