[백준 - 7490] 0 만들기

문제링크

fun main() {
    val bufferedReader = System.`in`.bufferedReader()
    val bufferedWriter = System.out.bufferedWriter()

    val testCase = bufferedReader.readLine().toInt()
    repeat(testCase) {
        val n = bufferedReader.readLine().toInt()
        calculateUsingDFS(n, 1, 1, 1, 0, "1")
        println()
    }

    bufferedReader.close()
    bufferedWriter.close()
}

fun calculateUsingDFS(n: Int, operand: Int, number: Int, sign: Int, sum: Int, expression: String) {
    if (number == n) {
        if (sum + sign * operand == 0) println(expression)
        return
    }
    val nextNumber = number + 1
    val operandWithSpace = operand * 10 + nextNumber
    calculateUsingDFS(n, operandWithSpace, nextNumber, sign, sum, "$expression $nextNumber")
    calculateUsingDFS(n, nextNumber, nextNumber, 1, sum + sign * operand, "$expression+$nextNumber")
    calculateUsingDFS(n, nextNumber, nextNumber, -1, sum + sign * operand, "$expression-$nextNumber")
}

주석 없는 코드를 만들기 위해 노력하는 개발자입니다.

혹시라도 의도가 분명하지 않아보이는 (이해가 되지 않는) 코드가 있으시다면 편하게 답변 달아주시면 정말 감사하겠습니다.