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.
Approach #1: C++.
class Solution {public: ???// Encodes a URL to a shortened URL. ???string encode(string longUrl) { ???????if (longToTiny.count(longUrl)) return baseUrl + longToTiny[longUrl]; ???????string tinyString = ""; ???????do { ???????????for (int i = 0; i < 6; ++i) { ???????????????//srand((unsigned)time(0)); ???????????????int index = rand() % characters.length(); ???????????????tinyString += characters[index]; ???????????} ???????????} while (longToTiny.count(tinyString)); ???????????????longToTiny[longUrl] = tinyString; ???????tinyToLong[baseUrl+tinyString] = longUrl; ???????????????return baseUrl + tinyString; ???} ???// Decodes a shortened URL to its original URL. ???string decode(string shortUrl) { ???????return tinyToLong[shortUrl]; ???} ???private: ???string baseUrl = "http://www.leetcode.com/"; ???string characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"; ???unordered_map<string, string> longToTiny; ???unordered_map<string, string> tinyToLong;};// Your Solution object will be instantiated and called as such:// Solution solution;// solution.decode(solution.encode(url));
Approach #2: Python.
class Codec: ???alphabet = string.ascii_letters + ‘0123456789‘ ???????def __init__(self): ???????self.url2code = {} ???????self.code2url = {} ???def encode(self, longUrl): ???????"""Encodes a URL to a shortened URL. ???????????????:type longUrl: str ???????:rtype: str ???????""" ???????while longUrl not in self.url2code: ???????????code = ‘‘.join(random.choice(Codec.alphabet) for _ in range(6)) ???????????if code not in self.code2url: ???????????????self.code2url[code] = longUrl ???????????????self.url2code[longUrl] = code ???????return ‘http://tinyurl.com/‘ + self.url2code[longUrl] ???????????def decode(self, shortUrl): ???????"""Decodes a shortened URL to its original URL. ???????????????:type shortUrl: str ???????:rtype: str ???????""" ???????return self.code2url[shortUrl[-6:]] ???????# Your Codec object will be instantiated and called as such:# codec = Codec()# codec.decode(codec.encode(url))
| Time Submitted | Status | Runtime | Language |
|---|---|---|---|
| a few seconds ago | Accepted | 28 ms | python |
| 2 minutes ago | Accepted | 36 ms | python |
| 13 minutes ago | Accepted | 8 ms | cpp |
535. Encode and Decode TinyURL(rand and srand)
原文地址：https://www.cnblogs.com/ruruozhenhao/p/9982455.html