Unique Morse Code Words

gistfile1.txt

let dictMap: [Character: String] = [
    "a":".-",
    "b":"-...",
    "c":"-.-.",
    "d": "-..",
    "e":".",
    "f":"..-.",
    "g":"--.",
    "h":"....",
    "i":"..",
    "j":".---",
    "k":"-.-",
    "l":".-..",
    "m":"--",
    "n":"-.",
    "o":"---",
    "p":".--.",
    "q":"--.-",
    "r":".-.",
    "s":"...",
    "t":"-",
    "u":"..-",
    "v":"...-",
    "w":".--",
    "x":"-..-",
    "y":"-.--",
    "z":"--.."
]

func uniqueMorse(_ words: [String]) -> Int {
    guard !words.isEmpty else { return 0 }
    var result = Set<String>()
    words.forEach { word in
        var morse = ""
        word.forEach({ character in
            morse += dictMap[character] ?? ".-"
        })
        result.insert(morse)
    }

    return result.count
}

uniqueMorse(["gin", "zen", "gig", "msg"])

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 "--...--.".

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.