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60 lines
2.1 KiB
Markdown
60 lines
2.1 KiB
Markdown
# [535. Encode and Decode TinyURL](https://leetcode.com/problems/encode-and-decode-tinyurl/)
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## 题目
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> Note: This is a companion problem to the System Design problem: Design TinyURL.
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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`.
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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.
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## 题目大意
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TinyURL是一种URL简化服务， 比如：当你输入一个URL [https://leetcode.com/problems/design-tinyurl](https://leetcode.com/problems/design-tinyurl) 时，它将返回一个简化的URL [http://tinyurl.com/4e9iAk](http://tinyurl.com/4e9iAk).
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要求：设计一个 TinyURL 的加密 encode 和解密 decode 的方法。你的加密和解密算法如何设计和运作是没有限制的，你只需要保证一个URL可以被加密成一个TinyURL，并且这个TinyURL可以用解密方法恢复成原本的URL。
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## 解题思路
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- 简单题。由于题目并无规定 `encode()` 算法，所以自由度非常高。最简单的做法是把原始 `URL` 存起来，并记录下存在字符串数组中的下标位置。`decode()` 的时候根据存储的下标还原原始的 `URL`。
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## 代码
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```go
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package leetcode
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import (
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"fmt"
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"strconv"
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"strings"
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)
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type Codec struct {
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urls []string
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}
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func Constructor() Codec {
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return Codec{[]string{}}
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}
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// Encodes a URL to a shortened URL.
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func (this *Codec) encode(longUrl string) string {
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this.urls = append(this.urls, longUrl)
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return "http://tinyurl.com/" + fmt.Sprintf("%v", len(this.urls)-1)
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}
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// Decodes a shortened URL to its original URL.
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func (this *Codec) decode(shortUrl string) string {
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tmp := strings.Split(shortUrl, "/")
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i, _ := strconv.Atoi(tmp[len(tmp)-1])
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return this.urls[i]
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}
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/**
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* Your Codec object will be instantiated and called as such:
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* obj := Constructor();
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* url := obj.encode(longUrl);
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* ans := obj.decode(url);
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*/
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``` |