# 535. Encode and Decode TinyURL

Medium
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.

### 解題

type Codec struct {
count int
}
func Constructor() Codec {
return Codec{ count: 0 }
}
// Encodes a URL to a shortened URL.
func (this *Codec) encode(longUrl string) string {
newStr := longUrl + " "
this.count++
return newStr
}
// Decodes a shortened URL to its original URL.
func (this *Codec) decode(shortUrl string) string {
return shortUrl[:len(shortUrl) - 1]
}
/**
* Your Codec object will be instantiated and called as such:
* obj := Constructor();
* url := obj.encode(longUrl);
* ans := obj.decode(url);
*/