Data commit

Task/Hailstone-sequence/Scala/hailstone-sequence.scala

@@ -0,0 +1,15 @@
+object HailstoneSequence extends App {
+  def hailstone(n: Int): Stream[Int] =
+    n #:: (if (n == 1) Stream.empty else hailstone(if (n % 2 == 0) n / 2 else n * 3 + 1))
+
+  val nr = args.headOption.map(_.toInt).getOrElse(27)
+  val collatz = hailstone(nr)
+  println(s"Use the routine to show that the hailstone sequence for the number: $nr.")
+  println(collatz.toList)
+  println(s"It has ${collatz.length} elements.")
+  println
+  println(
+    "Compute the number < 100,000, which has the longest hailstone sequence with that sequence's length.")
+  val (n, len) = (1 until 100000).map(n => (n, hailstone(n).length)).maxBy(_._2)
+  println(s"Longest hailstone sequence length= $len occurring with number $n.")
+}