https://www.cnblogs.com/gaochundong/p/complexity_of_algorithms.html
https://www.zhihu.com/question/21387264
https://blog.csdn.net/zolalad/article/details/11848739
https://www.jianshu.com/p/f4cca5ce055a
原文:https://www.cnblogs.com/JingWenxing/p/10094238.html