https://leetcode.com/articles/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:
[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]
Now, given a list of words, each word can be written as a concatenation of the Morse code of each letter. For example, "cab" 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: "gin" -> "--...-." "zen" -> "--...-." "gig" -> "--...--." "msg" -> "--...--." There are 2 different transformations, "--...-." and "--...--.".
public int uniqueMorseRepresentations(String[] words) {
String[] MORSE = new String[]{".-","-...","-.-.","-..",".","..-.","--.",
"....","..",".---","-.-",".-..","--","-.",
"---",".--.","--.-",".-.","...","-","..-",
"...-",".--","-..-","-.--","--.."};
Set<String> seen = new HashSet();
for (String word: words) {
StringBuilder code = new StringBuilder();
for (char c: word.toCharArray())
code.append(MORSE[c - 'a']);
seen.add(code.toString());
}
return seen.size();
}
