# Encode And Decode TinyURL Problem

## Description

LeetCode Problem 535.

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:

``````1
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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.

## Sample C++ Code

``````1
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class Solution {
public:
unordered_map<string, string> codeDB, urlDB;
const string chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

string getCode() {
string code = "";
for (int i = 0; i < 6; i++)
code += chars[rand() % 62];
return "http://tinyurl.com/" + code;
}

string encode(string longUrl) {
if (urlDB.find(longUrl) != urlDB.end())
return urlDB[longUrl];
string code = getCode();
while (codeDB.find(code) != codeDB.end())
code = getCode();
codeDB[code] = longUrl;
urlDB[longUrl] = code;
return code;
}

string decode(string shortUrl) {
return codeDB[shortUrl];
}
};

// Your Solution object will be instantiated and called as such:
// Solution solution;
// solution.decode(solution.encode(url));
``````