[프로그래머스] 피로도 - kotlin

XX게임에는 피로도 시스템(0 이상의 정수로 표현합니다)이 있으며, 일정 피로도를 사용해서 던전을 탐험할 수 있습니다. 이때, 각 던전마다 탐험을 시작하기 위해 필요한 "최소 필요 피로도"와 던전 탐험을 마쳤을 때 소모되는 "소모 피로도"가 있습니다. "최소 필요 피로도"는 해당 던전을 탐험하기 위해 가지고 있어야 하는 최소한의 피로도를 나타내며, "소모 피로도"는 던전을 탐험한 후 소모되는 피로도를 나타냅니다. 예를 들어 "최소 필요 피로도"가 80, "소모 피로도"가 20인 던전을 탐험하기 위해서는 유저의 현재 남은 피로도는 80 이상 이어야 하며, 던전을 탐험한 후에는 피로도 20이 소모됩니다.

import kotlin.math.max

class Solution {
    fun solution(k: Int, dungeons: Array<IntArray>): Int {
        var answer: Int = -1
        val useDungeons: MutableSet<Int> = mutableSetOf<Int>()

        answer = searchDungeons(k, dungeons, useDungeons)

        return answer
    }

    private fun searchDungeons(
        fatigue: Int,
        dungeons: Array<IntArray>,
        useDungeons: MutableSet<Int>
    ): Int {
        var cnt: Int = 0
        for ((idx, intArr) in dungeons.withIndex()) {
            if (useDungeons.contains(idx)) continue

            val limit = intArr[0]
            val cost = intArr[1]
            if (fatigue >= limit) {
                useDungeons.add(idx)
                cnt = max(cnt, searchDungeons(fatigue - cost, dungeons, useDungeons) + 1)
                useDungeons.remove(idx)
            }
        }

        return cnt
    }
}