535. Encode and Decode TinyURL - LeetCode

Question

535. Encode and Decode TinyURL

Solution

题目大意:实现长链接加密成短链接,短链接解密成长链接

思路:加密成短链接+key,将长链接按key保存到map,解密时根据短链接提取key,再从map中返回长链接

Java实现:

public class Codec { ???// https://leetcode.com/problems/design-tinyurl --> http://tinyurl.com/4e9iAk ???Map<Integer, String> map = new HashMap<>(); ???int i = 0; ???????// Encodes a URL to a shortened URL. ???public String encode(String longUrl) { ???????map.put(i, longUrl); ???????return "http://tinyurl.com/" + (i++); ???} ???// Decodes a shortened URL to its original URL. ???public String decode(String shortUrl) { ???????int key = Integer.parseInt(shortUrl.substring(shortUrl.lastIndexOf("/") + 1)); ???????return map.get(key); ???}}// Your Codec object will be instantiated and called as such:// Codec codec = new Codec();// codec.decode(codec.encode(url));

Ref

https://leetcode.com/problems/encode-and-decode-tinyurl/discuss/100270/Three-different-approaches-in-java

Using simple counter

public class Codec { ???Map<Integer, String> map = new HashMap<>(); ???int i=0; ???public String encode(String longUrl) { ???????map.put(i,longUrl); ???????return "http://tinyurl.com/"+i++; ???} ???public String decode(String shortUrl) { ???????return map.get(Integer.parseInt(shortUrl.replace("http://tinyurl.com/", ""))); ???}}

Using hashcode

public class Codec { ???Map<Integer, String> map = new HashMap<>(); ???public String encode(String longUrl) { ???????map.put(longUrl.hashCode(),longUrl); ???????return "http://tinyurl.com/"+longUrl.hashCode(); ???} ???public String decode(String shortUrl) { ???????return map.get(Integer.parseInt(shortUrl.replace("http://tinyurl.com/", ""))); ???}}

Using random function

public class Codec { ???Map<Integer, String> map = new HashMap<>(); ???Random r=new Random(); ???int key=r.nextInt(10000); ???public String encode(String longUrl) { ???????while(map.containsKey(key)) ???????????key= r.nextInt(10000); ???????map.put(key,longUrl); ???????return "http://tinyurl.com/"+key; ???} ???public String decode(String shortUrl) { ???????return map.get(Integer.parseInt(shortUrl.replace("http://tinyurl.com/", ""))); ???}}

535. Encode and Decode TinyURL - LeetCode

原文地址：https://www.cnblogs.com/okokabcd/p/9383836.html