535. Encode and Decode TinyURL.md

535. Encode and Decode TinyURL

Note: This is a companion problem to the System Design problem: Design TinyURL.

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.

Solution

• mine

public class Codec {
    public List<String> urls;
    // Encodes a URL to a shortened URL.
    public String encode(String longUrl) {
        if(urls == null){
            urls = new ArrayList<>();
        }
        urls.add(longUrl);
        return String.valueOf(urls.size()-1);
    }

    // Decodes a shortened URL to its original URL.
    public String decode(String shortUrl) {
         if(urls == null){
            return "";
         }else{
             return urls.get(Integer.parseInt(shortUrl));
         }
    }
}

// Your Codec object will be instantiated and called as such:
// Codec codec = new Codec();
// codec.decode(codec.encode(url));