535. TinyURL 的加密与解密-EXIAOHU Blog

题目链接：535. TinyURL 的加密与解密

在内部维护一个短 url 到长 url 的映射。

考虑大规模的短 url，可能会存在哈希冲突，需要引入随机化/编号。

考虑到分布式，需要雪花算法之类的复杂发号算法。

import string
from urllib.parse import urlparse


class NumberEncoder:
    alphabet = string.digits + string.ascii_letters
    idx = {k: i for i, k in enumerate(alphabet)}
    sign = '~'

    @classmethod
    def encode(cls, v: int) -> str:
        u, sign = '', ''

        if v < 0:
            sign = '~'
            v = -v

        if 0 <= v < len(cls.alphabet):
            return sign + cls.alphabet[v]

        while v != 0:
            v, i = divmod(v, len(cls.alphabet))
            u = cls.alphabet[i] + u

        return u + sign


class Codec:
    def __init__(self):
        self.urls: dict[str, str] = dict()

    def encode(self, longUrl: str) -> str:
        """Encodes a URL to a shortened URL.
        """
        path = f'/{NumberEncoder.encode(hash(longUrl))}'
        self.urls[path] = longUrl
        return f'http://s.t{path}'

    def decode(self, shortUrl: str) -> str:
        return self.urls.get(urlparse(shortUrl).path, '')