September 2017 Update

Task/Knuths-algorithm-S/Kotlin/knuths-algorithm-s.kotlin

@@ -0,0 +1,31 @@
+// version 1.1.2
+
+import java.util.Random
+
+class SOfN<T>(val n: Int) {
+    private val sample = ArrayList<T>(n)
+    private var i = 0
+
+    private companion object {
+        val rand = Random()
+    }
+
+    fun process(item: T): ArrayList<T> {
+        if (++i <= n)
+            sample.add(item)
+        else if (rand.nextInt(i) < n)
+            sample[rand.nextInt(n)] = item
+        return sample
+    }
+}
+
+fun main(args: Array<String>) {
+    val bin = IntArray(10)
+    (1..100_000).forEach {
+        val sOfn = SOfN<Int>(3)
+        var sample: ArrayList<Int>? = null
+        for (i in 0..9) sample = sOfn.process(i)
+        for (s in sample!!) bin[s]++
+    }
+    println(bin.contentToString())
+}