릿코드 997. Find the Town Judge 코틀린

trust배열의 2번쨰값이 n만큼 있는사람이 있고,해당번호가 한번도 신뢰건적이없으면 해당번호 리턴,없으면 -1리턴
n만큼 신뢰받은애들을 뽑아서,그중에서 신뢰건적이 없는애들을 찾자


정답

class Solution {
    fun findJudge(n: Int, trust: Array<IntArray>): Int {
        if (n==1){
            return 1
        }
        val trustMap = hashMapOf<Int, Int>()
        val giveTrustSet=mutableSetOf<Int>()
        for (i in trust){
            trustMap[i[1]]=trustMap[i[1]]?.plus(1)?:1
            giveTrustSet.add(i[0])
        }
        val candiJudgeList= mutableListOf<Int>()
        for ((key,value) in trustMap){
            if (value==n-1){
                candiJudgeList.add(key)
            }
        }
        println(candiJudgeList)
        for (i in candiJudgeList){
            if (!giveTrustSet.contains(i)){
                return i
            }
        }

        return -1
    }
}