LeetCode [535] Encode and Decode TinyURL

 535. Encode and Decode TinyURL

Medium

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.

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public class Codec { List<String> urls = new ArrayList<String>(); // Encodes a URL to a shortened URL. public String encode(String longUrl) { urls.add(longUrl); return String.valueOf(urls.size()-1); } // Decodes a shortened URL to its original URL. public String decode(String shortUrl) { int index = Integer.valueOf(shortUrl); return (index<urls.size())?urls.get(index):""; } } // Your Codec object will be instantiated and called as such: // Codec codec = new Codec(); // codec.decode(codec.encode(url));