Unique Morse Code Words

International Morse Code defines a standard encoding where each letter is mapped to a series of dots and dashes, as follows: "a" maps to ".-", "b" maps to "-...", "c" maps to "-.-.", and so on.

For convenience, the full table for the 26 letters of the English alphabet is given below:

[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]

Find the number of different transformations among all words we have.

Example:

Input: words = ["gin", "zen", "gig", "msg"]
Output: 2
Explanation: 
The transformation of each word is:
"gin" -> "--...-."
"zen" -> "--...-."
"gig" -> "--...--."
"msg" -> "--...--."
There are 2 different transformations, "--...-." and "--...--.". 

Approach:

Java

import java.util.HashSet;

public class UniqueMorseRepresentations {

    // define 1-26 char decode

    static String arr[] = { ".-", "-...", "-.-.", "-..", ".",

         "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--",

            "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-",

             "...-", ".--", "-..-", "-.--", "--.." };

    public static void main(String[] args) {

        String words[] = { "gin", "zen", "gig", "msg" };

        System.out.println(uniqueMorseRepresentations(words));

    }

    // method to find unique

    public static int uniqueMorseRepresentations(String[] words) {

        // create set for add unique string

        HashSet<String> s = new HashSet<>();

        // iterate till end of words

        for (int i = 0; i < words.length; i++) {

            StringBuffer sb = new StringBuffer();

            String w = words[i];

            // for each char

            for (int j = 0; j < w.length(); j++) {

                sb.append(arr[w.charAt(j) - 97]);

            }

            s.add(sb.toString());

        }

        return s.size();

    }

}

C++

#include <bits/stdc++.h>

using namespace std;

//function to find the unique 

//morse representation of all words

int uniqueMorseRepresentations(vector<string>& words) {

     map<char,string> mp;

     //unique morse code for each

     //character

    string arr[]={".-","-...","-.-.","-..",".",

             "..-.","--.","....","..",".---","-.-",

             ".-..","--","-.","---",".--.","--.-",

             ".-.","...","-","..-","...-",".--",

             "-..-","-.--","--.."}; 

     set<string> st;

      for(int i=0;i<26;i++)

              mp[i+'a']=arr[i];

        for(int i=0;i<words.size();i++)

        {

            string str="";

            for(int j=0;j<words[i].size();j++)

                   str+=mp[words[i][j]];

            st.insert(str);

        }

   return st.size();

 }

int main()

{

    vector<string> words = {"gin", "zen", "gig", "msg"};

    int unique=uniqueMorseRepresentations(words);

    cout<<unique<<"\n";

    return 0;

}