标签：target baseurl discus span self tar algorithm problems choice
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)
标签：target baseurl discus span self tar algorithm problems choice
原文地址：https://www.cnblogs.com/ruruozhenhao/p/9982455.html
