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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0501_0600.s0535_encode_and_decode_tinyurl;

// #Medium #String #Hash_Table #Design #Hash_Function
// #2022_08_02_Time_2_ms_(89.67%)_Space_42.1_MB_(96.88%)

import java.util.HashMap;
import java.util.Map;

/**
 * 535 - Encode and Decode TinyURL\.
 *
 * Medium
 *
 * > Note: This is a companion problem to the [System Design](https://leetcode.com/discuss/interview-question/system-design/) problem: [Design TinyURL](https://leetcode.com/discuss/interview-question/124658/Design-a-URL-Shortener-(-TinyURL-)-System/).
 *
 * 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 <= 10⁴
 * *   `url` is guranteed to be a valid URL.
**/
public class Codec {
    private Map map = new HashMap<>();
    private int n = 0;

    // Encodes a URL to a shortened URL.
    public String encode(String longUrl) {
        n++;
        String ans = "http://tinyurl.com/";
        ans += Integer.toString(n);
        map.put(ans, longUrl);
        return ans;
    }

    // Decodes a shortened URL to its original URL.
    public String decode(String shortUrl) {
        return map.get(shortUrl);
    }
}

// Your Codec object will be instantiated and called as such:
// Codec codec = new Codec();
// codec.decode(codec.encode(url));