[LeetCode] Problem 804 - Unique Morse Code Words

Posted on | In ,

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:

[“.-“,”-…”,”-.-.”,”-..”,”.”,”..-.”,”–.”,”….”,”..”,”.—“,”-.-“,”.-..”,”–”,”-.”,”—“,”.–.”,”–.-“,”.-.”,”…”,”-“,”..-“,”…-“,”.–”,”-..-“,”-.–”,”–..”]

Now, given a list of words, each word can be written as a concatenation of the Morse code of each letter. For example, “cba” can be written as “-.-..–…”, (which is the concatenation “-.-.” + “-…” + “.-“). We’ll call such a concatenation, the transformation of a word.

Return 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:

1
2
3
4
"gin" -> "--...-."
"zen" -> "--...-."
"gig" -> "--...--."
"msg" -> "--...--."

There are 2 different transformations, “–…-.” and “–…–.”.

Note

The length of words will be at most 100.
Each words[i] will have length in range [1, 12].
words[i] will only consist of lowercase letters.

Code

1
2
3
4
5
6
7
8
9
10
11
12
13
14
public int uniqueMorseRepresentations(String[] words) {
    Set<String> result = new HashSet<>();
    String[] morse = {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",                    ".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
    for (String word : words) {
        String str = "";

        for (char ch : word.toCharArray())
            str += morse[ch - 'a'];
        
        result.add(str);
    }

    return result.size();
}