September 2017 Update

Task/Power-set/Kotlin/power-set.kotlin

@@ -0,0 +1,38 @@
+// version 1.1.3
+
+class PowerSet<T>(val items: List<T>) {
+    private lateinit var combination: IntArray
+
+    init {
+        println("Power set of $items comprises:")
+        for (m in 0..items.size) {
+            combination = IntArray(m)
+            generate(0, m)
+        }
+    }
+
+    private fun generate(k: Int, m: Int) {
+        if (k >= m) {
+            println(combination.map { items[it] })
+        }
+        else {
+            for (j in 0 until items.size)
+                if (k == 0 || j > combination[k - 1]) {
+                    combination[k] = j
+                    generate(k + 1, m)
+                }
+        }
+    }
+}
+
+fun main(args: Array<String>) {
+    val itemsList = listOf(
+        listOf(1, 2, 3, 4),
+        emptyList<Int>(),
+        listOf(emptyList<Int>())
+    )
+    for (items in itemsList) {
+        PowerSet(items)
+        println()
+    }
+}