说明：  分别采用最佳(Optimal)置换算法、先进先出(FIFO)页面置换算法和最近最少使用(LRU)置换算法对用户输入的页面号请求序列进行淘汰和置换，从而加深对页面置换算法的理解。
(Adopt the best (Optimal) replacement algorithm, first in first out (FIFO) page replacement algorithm and least recently used (LRU) replacement algorithm for the user to enter the page number request sequences are eliminated and the displacement, so as to deepen the understanding of page replacement algorithm.)