垃圾回收算法

https://blog.csdn.net/yrwan95/article/details/82829186?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522162035656616780357233123%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=162035656616780357233123&biz_id=0&utm_medium=distribute.wap_search_result.none-task-blog-2_alltop_positive~default-1-82829186.wap_first_rank_v2_rank_v29&utm_term=%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%E7%AE%97%E6%B3%95&spm=1018.2118.3001.4187