[알고리즘] 코틀린 스럽게 코딩하기 - 프로그래머스 42889 실패율

var 진짜 쓰기 싫었는데!

class Solution {
    fun solution(N: Int, stages: IntArray): List<Int> {
        var challengerCnt = stages.size
        val keepCntByStage = (1..N).associateWith { stage ->
            stages.count { it == stage }
        }

        return keepCntByStage.entries.map { (stage, peopleCnt) ->
            val failRate = (0.0).takeIf { challengerCnt == 0 } ?: (peopleCnt / challengerCnt.toDouble())
            challengerCnt -= peopleCnt
            stage to failRate
        }.sortedWith ( compareByDescending<Pair<Int, Double>> { it.second }.thenBy { it.first })
            .map { it.first }
    }
}