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.
Python Solution 1:
class Codec:
def __init__(self):
self.d = {}
self.l = {}
def encode(self, longUrl):
"""Encodes a URL to a shortened URL.
:type longUrl: str
:rtype: str
"""
if longUrl in self.l:
return self.l[longUrl]
while True:
random_string = "".join(random.choice(string.ascii_uppercase + string.digits) for _ in range(10))
if random_string not in self.d:
self.d[random_string] = longUrl
self.l[longUrl] = random_string
break
return random_string
def decode(self, shortUrl):
"""Decodes a shortened URL to its original URL.
:type shortUrl: str
:rtype: str
"""
return self.d[shortUrl]
# Your Codec object will be instantiated and called as such:
# codec = Codec()
# codec.decode(codec.encode(url))
Python Solution 2:
class Codec:
chars = string.ascii_letters + string.digits
def __init__(self):
self.codetourl = {}
def encode(self, longUrl):
"""Encodes a URL to a shortened URL.
:type longUrl: str
:rtype: str
"""
while True:
code = ''.join(random.choice(Codec.chars) for _ in range(6))
if code not in self.codetourl: break
self.codetourl[code] = longUrl
return 'http://tinyurl.com/' + code
def decode(self, shortUrl):
"""Decodes a shortened URL to its original URL.
:type shortUrl: str
:rtype: str
"""
code = shortUrl.split('/')[-1]
return self.codetourl.get(code, "")
# Your Codec object will be instantiated and called as such:
# codec = Codec()
# codec.decode(codec.encode(url))
Summary:
- https://discuss.leetcode.com/topic/81637/two-solutions-and-thoughts
- He's really clever.
LeetCode: 535. Encode and Decode TinyURL
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