535.tiny-url-的加密与解密.md

535.tiny-url-的加密与解密

/*
 * @lc app=leetcode.cn id=535 lang=typescript
 *
 * [535] TinyURL 的加密与解密
 */

// @lc code=start

/**
 * Encodes a URL to a shortened URL.
 */
function encode(longUrl: string): string {}

/**
 * Decodes a shortened URL to its original URL.
 */
function decode(shortUrl: string): string {}

/**
 * Your functions will be called as such:
 * decode(encode(strs));
 */
// @lc code=end

解法 1: 哈希表

const map = new Map<string, string>()
const chs: string[] = []
for (let i = 0; i < 26; i++) chs.push(String.fromCharCode(i + 65))
for (let i = 0; i < 26; i++) chs.push(String.fromCharCode(i + 97))
for (let i = 0; i < 10; i++) chs.push(i + '')
const random = () => {
  const res: string[] = []
  for (let i = 0; i < 10; i++) {
    const ch = chs[Math.floor(Math.random() * chs.length)]
    res.push(ch)
  }
  return res.join('')
}

function encode(longUrl: string): string {
  let str = random()
  while (map.has(str)) str = random()
  map.set(str, longUrl)
  return str
}

function decode(shortUrl: string): string {
  return map.get(shortUrl)!
}