--- a/testing3-bak/knight3.scala	Thu Nov 22 17:35:30 2018 +0000
+++ b/testing3-bak/knight3.scala	Thu Nov 22 23:00:57 2018 +0000
@@ -1,96 +1,63 @@
 // Part 3 about finding a single tour using the Warnsdorf Rule
 //=============================================================
 
-object CW7c {
+//object CW8c { // for preparing the jar
 
 type Pos = (Int, Int)
 type Path = List[Pos]
 
+
+// for measuring time in the JAR
+def time_needed[T](code: => T) : T = {
+  val start = System.nanoTime()
+  val result = code
+  val end = System.nanoTime()
+  println(f"Time needed: ${(end - start) / 1.0e9}%3.3f secs.")
+  result
+}
+
+
 def print_board(dim: Int, path: Path): Unit = {
   println
   for (i <- 0 until dim) {
     for (j <- 0 until dim) {
-      print(f"${path.reverse.indexOf((i, j))}%3.0f ")
+      print(f"${path.reverse.indexOf((i, j))}%4.0f ")
     }
     println
   } 
 }
 
-def add_pair(x: Pos)(y: Pos): Pos = 
+def add_pair(x: Pos, y: Pos): Pos = 
   (x._1 + y._1, x._2 + y._2)
 
-def is_legal(dim: Int, path: Path)(x: Pos): Boolean = 
+def is_legal(dim: Int, path: Path, x: Pos): Boolean = 
   0 <= x._1 && 0 <= x._2 && x._1 < dim && x._2 < dim && !path.contains(x)
 
 def moves(x: Pos): List[Pos] = 
   List(( 1,  2),( 2,  1),( 2, -1),( 1, -2),
-       (-1, -2),(-2, -1),(-2,  1),(-1,  2)).map(add_pair(x))
+       (-1, -2),(-2, -1),(-2,  1),(-1,  2)).map(add_pair(x, _))
 
 def legal_moves(dim: Int, path: Path, x: Pos): List[Pos] = 
-  moves(x).filter(is_legal(dim, path))
-
+  moves(x).filter(is_legal(dim, path, _))
+ 
 def ordered_moves(dim: Int, path: Path, x: Pos): List[Pos] = 
   legal_moves(dim, path, x).sortBy((x) => legal_moves(dim, path, x).length)
 
-
 import scala.annotation.tailrec
 
 @tailrec
-def first(xs: List[Pos], f: Pos => Option[Path]): Option[Path] = xs match {
+def tour_on_mega_board_aux(dim: Int, paths: List[Path]): Option[Path] = paths match {
   case Nil => None
-  case x::xs => {
-    val result = f(x)
-    if (result.isDefined) result else first(xs, f)
-  }
+  case (path::rest) =>
+    if (path.length == dim * dim) Some(path)
+    else tour_on_mega_board_aux(dim, ordered_moves(dim, path, path.head).map(_::path) ::: rest)
 }
 
-
-def first_closed_tour_heuristic(dim: Int, path: Path): Option[Path] = {
-  if (path.length == dim * dim && moves(path.head).contains(path.last)) Some(path)
-  else
-    first(ordered_moves(dim, path, path.head), (x: Pos) => first_closed_tour_heuristic(dim, x::path))
-}
-
-/*
-for (dim <- 1 to 6) {
-  val t = first_closed_tour_heuristic(dim, List((dim / 2, dim / 2)))
-  println(s"${dim} x ${dim} closed: " + (if (t == None) "" else { print_board(dim, t.get) ; "" }))
-}*/
+def ttour_on_mega_board(dim: Int, path: Path): Option[Path] =
+  tour_on_mega_board_aux(dim, List(path))
 
 
-def first_tour_heuristic(dim: Int, path: Path): Option[Path] = {
-
-  @tailrec
-  def aux(dim: Int, path: Path, moves: List[Pos]): Option[Path] =  
-  if (path.length == dim * dim) Some(path)
-  else
-    moves match {
-      case Nil => None
-      case x::xs => {
-        val r = first_tour_heuristic(dim, x::path)
-        if (r.isDefined) r else aux(dim, path, xs)
-    }
-  }    
- 
-  aux(dim, path, ordered_moves(dim, path, path.head)) 
-}
+def tour_on_mega_board(dim: Int, path: Path) =
+  time_needed(ttour_on_mega_board(dim: Int, path: Path))
 
-/*
-def first_tour_heuristic(dim: Int, path: Path): Option[Path] = {
-  if (path.length == dim * dim) Some(path)
-  else
-    first(ordered_moves(dim, path, path.head), (x: Pos) => first_tour_heuristic(dim, x::path))
-}
-*/
-
-/*
-for (dim <- 1 to 50) {
-  val t = first_tour_heuristic(dim, List((dim / 2, dim / 2)))
-  println(s"${dim} x ${dim}: " + (if (t == None) "" else { print_board(dim, t.get) ; "" }))
-}
-*/
-
-}
-
-
-//CW7c.first_tour_heuristic(50, List((0,0))).get
+//}