leetcode535 Encode and Decode TinyURL java

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

思路

我的理解这道题是把String给压缩，之后再想办法给还原~~

List<String> urls = new ArrayList<>();
public String encode(String longUrl) {
urls.add(longUrl);
return String.valueOf(urls.size() - 1);
}

public String decode(String shortUrl) {
int index = Integer.valueOf(shortUrl);
return(urls.size()>index ? urls.get(index) : "");
}