12 构建模式：想要车还是庄园

参考资料

https://learn.lianglianglee.com/%e4%b8%93%e6%a0%8f/%e7%99%bd%e8%af%9d%e8%ae%be%e8%ae%a1%e6%a8%a1%e5%bc%8f%2028%20%e8%ae%b2%ef%bc%88%e5%ae%8c%ef%bc%89/12%20%e6%9e%84%e5%bb%ba%e6%a8%a1%e5%bc%8f%ef%bc%9a%e6%83%b3%e8%a6%81%e8%bd%a6%e8%bf%98%e6%98%af%e5%ba%84%e5%9b%ad.md