1.https://blog.csdn.net/xzll123/article/details/122318291 (洗牌)

2.https://blog.csdn.net/qq_33514421/article/details/84076653?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522166144239416781685317956%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=166144239416781685317956&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~top_positive~default-1-84076653-null-null.142^v42^pc_rank_34_ecpm25,185^v2^control&utm_term=%E6%89%93%E5%8D%B0%E6%B2%99%E6%BC%8F&spm=1018.2226.3001.4187 (打印沙漏)