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804. Unique Morse Code Words

Easy

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:

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

Given an array of strings words where 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 of "-.-.", ".-", and "-...". We will call such a concatenation the transformation of a word.

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

Solution

class Solution:
    def __init__(self):
        self.morse = [
            ".-",
            "-...",
            "-.-.",
            "-..",
            ".",
            "..-.",
            "--.",
            "....",
            "..",
            ".---",
            "-.-",
            ".-..",
            "--",
            "-.",
            "---",
            ".--.",
            "--.-",
            ".-.",
            "...",
            "-",
            "..-",
            "...-",
            ".--",
            "-..-",
            "-.--",
            "--..",
        ]

    def uniqueMorseRepresentations(self, words: List[str]) -> int:
        translations = set()

        for word in words:
            translation = []
            for c in word:
                translation.append(self.morse[ord(c) - ord("a")])

            translations.add("".join(translation))

        return len(translations)