check sum 6

sum6.kt

    fun checkToSix() {
        val list = ArrayList<String>()
//        val src = listOf(2,2,2)
        (2..9)
                .map {
                    System.out.println(it)
                    listOf(it, it, it)
                }
                .forEach {
                    list.clear()
                    if (toSix(0, it, 0, 6, list)) {
                        System.out.println(list)
                    }
                }
    }
    fun toSix(init: Int, src: List<Int>, index:Int, remain: Int, list: ArrayList<String>): Boolean {
        if (index >= src.size) {
            return false
        }
        when{
            init+src[index] == remain -> {
                list.add("+${src[index]}")
                return true
            }
            init-src[index] == 6 -> {
                list.add("-${src[index]}")
                return true
            }
            init*src[index] == 6 -> {
                list.add("*${src[index]}")
                return true
            }
            init/src[index] == 6 -> {
                list.add("/${src[index]}")
                return true
            }
            Math.pow(init.toDouble(), src[index].toDouble()).toInt() == 6 -> {
                list.add("^${src[index]}")
                return true
            }
            init % src[index] == 6 -> {
                list.add("%${src[index]}")
                return true
            }
            else -> {
                if (toSix(init + src[index], src, index + 1, remain, list)) {
                    list.add("+${src[index]}")
                    return true
                }
                if (toSix(init - src[index], src, index + 1, remain, list)) {
                    list.add("-${src[index]}")
                    return true
                }
                if (toSix(init * src[index], src, index + 1, remain, list)) {
                    list.add("*${src[index]}")
                    return true
                }
                if (toSix(init / src[index], src, index + 1, remain, list)) {
                    list.add("/${src[index]}")
                    return true
                }
                if (toSix(Math.pow(init.toDouble(), src[index].toDouble()).toInt() , src, index + 1, remain, list)) {
                    list.add("^${src[index]}")
                    return true
                }
                if (toSix(init / src[index], src, index + 1, remain, list)) {
                    list.add("%${src[index]}")
                    return true
                }
            }
        }
        return false
    }