535. Encode and Decode TinyURL - LeetCode
阿新 • • 發佈:2018-07-29
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Question
535. Encode and Decode TinyURL
Solution
題目大意:實現長鏈接加密成短鏈接,短鏈接解密成長鏈接
思路:加密成短鏈接+key,將長鏈接按key保存到map,解密時根據短鏈接提取key,再從map中返回長鏈接
Java實現:
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