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# 535. Encode and Decode TinyURL
from string import ascii_letters
from random import choice
"""
tinyurl is a url shortening service where you enter a url such as
https://looooooongurl.com and it returns a short url such as
http://tinyurl.com/4e9iAk. design a class to encode a url and decode a tiny
url. 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.
"""
class Codec:
alphabet = ascii_letters + "0123456789"
def __init__(self):
self.url_code = {}
self.code_url = {}
def encode(self, longUrl):
"""Encodes a URL to a shortened URL.
:type longUrl: str
:rtype: str
"""
while longUrl not in self.url_code:
code = "".join(choice(Codec.alphabet) for _ in range(6))
if code not in self.code_url:
self.code_url[code] = longUrl
self.url_code[longUrl] = code
return "http://tinyurl.com/" + self.url_code[longUrl]
def decode(self, shortUrl):
"""Decodes a shortened URL to its original URL.
:type shortUrl: str
:rtype: str
"""
return self.code_url[shortUrl[-6:]]
if __name__ == "__main__":
obj = Codec()
print(obj.decode(obj.encode("https://leetcode.com/problems/design-tinyurl")))
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