EncodeandDecodeTinyURL.java

// SC : O(n), no of urls that you have encoded
// TC : O(1)
public class Codec {

    Map<String, String> map = new HashMap<>();
    // Encodes a URL to a shortened URL.
    public String encode(String longUrl) {
        String key = ""+map.size();
        map.put(key, longUrl);
        return key;
    }

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

public class Codec {

    Map<String, String> map = new HashMap<>();

    // Encodes a URL to a shortened URL.
    public String encode(String longUrl) {
        String key = ""+longUrl.hashCode();
        map.put(key, longUrl);
        return key;
    }

    // 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));