LeetCode之Unique Morse Code Words（Kotlin）

問題： 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.

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方法： 將字串組中的字串轉換成morse電碼並存入set中，最後輸出set中元素的個數即為結果。（set不儲存重複元素）

具體實現：

class UniqueMorseCodeWords {
    private val morse = arrayOf(".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--..")

    fun uniqueMorseRepresentations(words: Array<String>): Int {
        val mutableSet = words
                .map { trans(it) }
                .toSet()
        return mutableSet.size
    }

    private fun trans(str : String): String {
        val sb = StringBuilder()
        for (ch in str) {
            sb.append(morse[ch.toInt() % 'a'.toInt()])
        }
        return sb.toString()
    }
}

fun main(args: Array<String>) {
    val words = arrayOf("gin", "zen", "gig", "msg")
    val uniqueMorseCodeWords = UniqueMorseCodeWords()
    println(uniqueMorseCodeWords.uniqueMorseRepresentations(words))
}
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具體程式碼實現可以參考Github