What is the 100th word in the permutation of "GAKKOU"? in Kotlin

GAKKOU.kt

fun main() {
    val string = "GAKKOU"
    val chars: List<Char> = string.toList()

    val word = chars.permutations().distinct().map { it.toCharArray().concatToString() }.sorted()[99]
    println(word)
}

fun <T> List<T>.permutations(): List<List<T>> {
    if (this.isEmpty()) return listOf(emptyList())

    val result: MutableList<List<T>> = mutableListOf()
    for (i in this.indices) {
        (this - this[i]).permutations().forEach {
            item -> result.add(item + this[i])
        }
    }
    return result
}