Data commit

Task/Topswops/Scala/topswops.scala

@@ -0,0 +1,32 @@
+object Fannkuch extends App {
+
+  def fannkuchen(l: List[Int], n: Int, i: Int, acc: Int): Int = {
+    def flips(l: List[Int]): Int = (l: @unchecked) match {
+      case 1 :: ls => 0
+      case (n :: ls) =>
+        val splitted = l.splitAt(n)
+        flips(splitted._2.reverse_:::(splitted._1)) + 1
+    }
+
+    def rotateLeft(l: List[Int]) =
+      l match {
+        case Nil => List()
+        case x :: xs => xs ::: List(x)
+      }
+
+    if (i >= n) acc
+    else {
+      if (n == 1) acc.max(flips(l))
+      else {
+        val split = l.splitAt(n)
+        fannkuchen(rotateLeft(split._1) ::: split._2, n, i + 1, fannkuchen(l, n - 1, 0, acc))
+      }
+    }
+  } // def fannkuchen(
+
+  val result = (1 to 10).map(i => (i, fannkuchen(List.range(1, i + 1), i, 0, 0)))
+  println("Computing results...")
+  result.foreach(x => println(s"Pfannkuchen(${x._1})\t= ${x._2}"))
+  assert(result == Vector((1, 0), (2, 1), (3, 2), (4, 4), (5, 7), (6, 10), (7, 16), (8, 22), (9, 30), (10, 38)), "Bad results")
+  println(s"Successfully completed without errors. [total ${scala.compat.Platform.currentTime - executionStart} ms]")
+}