Josephus problem in Kotlin

Josephus.kt

data class Soldier(val position: Int, var state:State = State.Living) {
    fun suicide() {
        state = State.Dead
    }
    fun isAlive() = state == State.Living
}

enum class State {
    Living, Dead
}

class DeathCircle(val size: Int, val step: Int) {

    val soldiers = Array( size, {Soldier(it)}).toList()

    fun findSurvivor(): Soldier {
        var soldier = soldiers.first()
        (2..size).forEach {
            (1..step).forEach {
                soldier = soldier.nextLivingSoldier()
            }
            soldier.suicide()
        }
        return soldier.nextLivingSoldier()
    }

    tailrec fun Soldier.nextLivingSoldier():Soldier =
            if (next().isAlive())
                next()
            else
                next().nextLivingSoldier()

    fun Soldier.next() = soldiers.get(
            if (position == size - 1)
                0
            else
                position + 1
    )
}