实现cache替换算法，思路是改进的LRU和LFU算法，在一定程度上提高了原来的LRU算法的命中率。-Achieve cache replacement algorithm, idea is to improve the LRU and LFU algorithms, to a certain extent, the original LRU algorithm to improve the hit rate.

cache 模拟器：支持LRU和random两种替换策略-cache simulator: support LRU and random replacement strategies