Design an algorithm to encodea list of stringstoa string. The encoded string is then sent over the network and is decoded back to the original list of strings.

Machine 1 (sender) has the function:

string encode(vector
<
string
>
 strs) {
  // ... your code
  return encoded_string;
}

Machine 2 (receiver) has the function:

vector
<
string
>
 decode(string s) {
  //... your code
  return strs;
}

So Machine 1 does:

string encoded_string = encode(strs);

and Machine 2 does:

vector
<
string
>
 strs2 = decode(encoded_string);

strs2in Machine 2 should be the same asstrsin Machine 1.

Implement theencodeanddecodemethods.

Note:

• The string may contain any possible characters out of 256 valid ascii characters. Your algorithm should be generalized enough to work on any possible characters.
• Do not use class member/global/static variables to store states. Your encode and decode algorithms should be stateless.
• Do not rely on any library method such as eval or serialize methods. You should implement your own encode/decode algorithm.

public class Codec {

    // Encodes a list of strings to a single string.
    public String encode(List<String> strs) {
        StringBuilder sb = new StringBuilder();

        for (String str : strs){
            sb.append(str.length() + "/" + str);
        }

        return sb.toString();
    }

    // Decodes a single string to a list of strings.
    public List<String> decode(String s) {
        List<String> ans = new ArrayList<>();
        int i = 0;

        while (i < s.length()){
            int slash = s.indexOf("/", i);
            int len = Integer.valueOf(s.substring(i, slash));
            String str = s.substring(slash + 1, slash + len + 1);
            ans.add(str);

            i = slash + len + 1;
        }

        return ans;
    }
}

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

public class Codec {

    Map<String, List<String>> hash = new HashMap<>();

    // Encodes a list of strings to a single string.
    public String encode(List<String> strs) {
        String key = genKey();
        while (hash.containsKey(key)){
            key = genKey();
        }

        hash.put(key, strs);

        return key;
    }

    // Decodes a single string to a list of strings.
    public List<String> decode(String s) {
        return hash.get(s);
    }

    private String genKey(){

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 6; i++){
            int offset = (int)(Math.random() * 26);
            char c = 'a';
            c += offset;
            sb.append(c);
        }

        System.out.println(sb.toString());
        return sb.toString();
    }
}

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