从Kotlin中的多组字符计算所有可能的字符串

fun calculateAllPossibleStrings(characters: Array<CharArray>): List<String> {
    val result = mutableListOf<String>()
    calculateStrings(characters, 0, "", result)
    return result
}

fun calculateStrings(characters: Array<CharArray>, index: Int, currentString: String, result: MutableList<String>) {
    if (index == characters.size) {
        result.add(currentString)
        return
    }
    
    val currentCharacters = characters[index]
    for (char in currentCharacters) {
        calculateStrings(characters, index + 1, currentString + char, result)
    }
}

fun main() {
    val characters = arrayOf(
        charArrayOf('a', 'b'),
        charArrayOf('c', 'd', 'e'),
        charArrayOf('f', 'g')
    )
    
    val possibleStrings = calculateAllPossibleStrings(characters)
    for (string in possibleStrings) {
        println(string)
    }
}

acf
acg
adf
adg
aef
aeg
bcf
bcg
bdf
bdg
bef
beg