[Kotlin] 튜플

class Solution {
    fun solution(s: String): IntArray {
        val pattern = "\\{(\\d+(,\\d+)*)\\}".toRegex()

        return pattern
            .findAll(s)
            .flatMap {
                it.value.substring(1, it.value.length - 1)
                    .split(",")
            }
            .groupBy { it }
            .mapValues { it.value.size }
            .toList()
            .sortedBy { it.second }
            .reversed()
            .map { Integer.parseInt(it.first) }
            .toIntArray()
    }
}