cc-2018-03-30

kotlin.kt

infix fun Int.toThePowerOf(exponent: Int): Int = Math.pow(this.toDouble(), exponent.toDouble()).toInt()

fun main(args: Array<String>) {
    val sets = mutableListOf<Set<String>>()

    sets.add(emptySet())

    for(setNumber in 1 until 2.toThePowerOf(args.size)) {
        val set = mutableSetOf<String>()

        for(itemNumber in 0 until args.size) {
            if (2 toThePowerOf itemNumber and setNumber != 0) {
                set.add(args[itemNumber])
            }
        }

        sets.add(set)
    }

    println(sets)
}