Leetcode刷题之路(Python)——535. Encode and Decode TinyURL

题目的链接：https://leetcode.com/problems/encode-and-decode-tinyurl/description/

       “TinyURL is a URL shortening service where you enter a URL such as https://leetcode.com/problems/design-tinyurl and it returns a short URL such as http://tinyurl.com/4e9iAk.
      Design the encode and decode methods for the TinyURL service. There is no restriction on how your encode/decode algorithm should work. You just need to ensure that a URL can be encoded to a tiny URL and the tiny URL can be decoded to the original URL.”

      TinyUrl是一个精简URL的服务器。功能就是输入一个URL，例如：https://leetcode.com/problems/design-tinyurl 它会返回一个精简后的地址，例如：http://tinyurl.com/4e9iAk.
      我们的任务是要设计encode(编码)和decode(解码)这两个函数。对于两个函数的工作原理不做限制，我们只用保证的是：一个URL可以被编码为一个简短的URL，并且这个间断的URL可以被解码为原来的URL。

解题思路

      我们的主要任务是写两个函数：encode、decode。先把encode编好，decode根据encode的短URL，直接可以读取原始的URL。对于encode要考虑几个问题：