릿코드 1239. Maximum Length of a Concatenated String with Unique Characters 코틀린

크기가 작아서 o(n^3)까지도 될듯
재귀로 모든 조합을 더해가면서(dfs),현재 조건을 만족하지못하면 끝내고,조건을 만족하면 계속 들어가는식으로 길이max리턴

정답

import kotlin.math.max

class Solution {
    fun maxLength(arr: List<String>): Int {
        var maxValue=0
        for ((index,value) in arr.withIndex()){
            maxValue=max(maxValue,maxLengthFind(value,arr.subList(index+1,arr.size)))
            //println("""${"aaa".length},${"aaa".toSet()}""")
        }
        println(maxValue)
        return maxValue
    }
    fun maxLengthFind(curStr:String,arr: List<String>):Int{
        var maxValue=curStr.length
        val curSet = curStr.toSet()
        if (curStr.length!=curSet.size){
            return -1
        }
        for ((index,value) in arr.withIndex()) {
            maxValue = max(maxValue, maxLengthFind(curStr+value,arr.subList(index+1,arr.size)))
        }
        return maxValue
    }

}