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.
1 public class Codec { 2 ????private const string pref = "http://tinyurl.com/"; 3 ?????4 ????// in thoery should use a hash founction 5 ????private int counter = 0; 6 ????private Dictionary<int, string> hashToUrl = new Dictionary<int, string>(); 7 ????private Dictionary<string, int> urlToHash = new Dictionary<string, int>(); 8 ?????9 ????// Encodes a URL to a shortened URL10 ????public string encode(string longUrl) {11 ????????if (!urlToHash.ContainsKey(longUrl))12 ????????{13 ????????????urlToHash[longUrl] = counter;14 ????????????hashToUrl[counter] = longUrl;15 ????????????counter++; ???16 ????????}17 ????????18 ????????return pref + urlToHash[longUrl];19 ????}20 21 ????// Decodes a shortened URL to its original URL.22 ????public string decode(string shortUrl) {23 ????????int hash = Int32.Parse(shortUrl.Substring(19, shortUrl.Length - 19));24 ????????25 ????????return hashToUrl[hash];26 ????}27 }28 29 // Your Codec object will be instantiated and called as such:30 // Codec codec = new Codec();31 // codec.decode(codec.encode(url));Leetcode 535: Encode and Decode TinyURL
原文地址：https://www.cnblogs.com/liangmou/p/8175547.html