题目要求
编写一个类，提供两个方法。一个可以将普通的网址编码成短网址，一个可以将短网址还原为普通网址。
参考题解
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import random
import math
import re
class Codec:
charbase = [x for x in "0123456789abcdefghijklmnopqrstuvwxyz"]
urldict = {}
longurldict = {}
def get_random_char(self, length):
random_char = ""
for x in range(6):
random_char += self.charbase[math.ceil(random.random() * len(self.charbase) ) - 1 ]
return random_char
def encode(self, longUrl):
if longUrl in self.longurldict:
return self.longurldict[longUrl]
url_code = self.get_random_char(6)
if url_code in self.urldict:
self.encode(longUrl)
else:
self.longurldict[longUrl] = url_code
self.urldict[url_code] = longUrl
return "http://tinyurl.com/" + url_code
def decode(self, shortUrl):
domain = "http://tinyurl.com/"
shortUrl = shortUrl.replace(domain, "")
if shortUrl in self.urldict:
return self.urldict[shortUrl]
else:
return false
url = "https://leetcode.com/problems/design-tinyurl";
codec = Codec()
print(codec.get_random_char(6))
print(codec.get_random_char(6))
print(codec.get_random_char(6))
print(codec.get_random_char(6))
print(codec.get_random_char(6))
print(codec.encode(url))
print(codec.decode(codec.encode(url)))
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我这个过程遇到一个坑，本地环境是Python3，math.ceil函数返回了整型数，Leetcode是Python2的环境，所以返回了浮点数，需要做一下类型转换。看了一下其他解题方法，其实可以直接用 hash 函数，不用考虑那么多。
