[1.1 程序设计的基本元素](%E6%9E%84%E9%80%A0%E8%BF%87%E7%A8%8B%E6%8A%BD%E8%B1%A1/%E7%A8%8B%E5%BA%8F%E8%AE%BE%E8%AE%A1%E7%9A%84%E5%9F%BA%E6%9C%AC%E5%85%83%E7%B4%A0.md) [1.3 用高阶函数做抽象](%E6%9E%84%E9%80%A0%E8%BF%87%E7%A8%8B%E6%8A%BD%E8%B1%A1/1.3%E7%94%A8%E9%AB%98%E9%98%B6%E5%87%BD%E6%95%B0%E5%81%9A%E6%8A%BD%E8%B1%A1.md)