# 2022-06-29

## 535. Encode and Decode TinyURL

### Description

Note: This is a companion problem to the System Design problem: Design TinyURL.

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 a class to encode a URL and decode a tiny URL.

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.

Implement the `Solution` class:

• `Solution()` Initializes the object of the system.

• `String encode(String longUrl)` Returns a tiny URL for the given `longUrl`.

• `String decode(String shortUrl)` Returns the original long URL for the given `shortUrl`. It is guaranteed that the given `shortUrl` was encoded by the same object.

Example 1:

``````Input: url = "https://leetcode.com/problems/design-tinyurl"
Output: "https://leetcode.com/problems/design-tinyurl"

Explanation:
Solution obj = new Solution();
string tiny = obj.encode(url); // returns the encoded tiny url.
string ans = obj.decode(tiny); // returns the original url after deconding it.``````

Constraints:

• `1 <= url.length <= 10^4`

• `url` is guranteed to be a valid URL.

### Solution

#### Approach #0

``````type Codec struct {
id int
m map[string]string
}

func Constructor() Codec {
return Codec{m:make(map[string]string)}
}

// Encodes a URL to a shortened URL.
func (this *Codec) encode(longUrl string) (tiny string) {
this.id++
tiny=strconv.Itoa(this.id)
this.m[tiny]=longUrl
return
}

// Decodes a shortened URL to its original URL.
func (this *Codec) decode(shortUrl string) string {
return this.m[shortUrl]
}

/**
* Your Codec object will be instantiated and called as such:
* obj := Constructor();
* url := obj.encode(longUrl);
* ans := obj.decode(url);
*/``````

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