--- a/main_testing4-old/knight3.scala	Fri Apr 26 17:29:30 2024 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,73 +0,0 @@
-// Part 3 about finding a single tour using the Warnsdorf Rule
-//=============================================================
-
-object M4c { // 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))}%4.0f ")
-    }
-    println()
-  } 
-}
-
-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 = 
-  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, _))
-
-def legal_moves(dim: Int, path: Path, x: Pos): List[Pos] = 
-  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 tour_on_mega_board_aux(dim: Int, paths: List[Path]): Option[Path] = paths match {
-  case Nil => None
-  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 ttour_on_mega_board(dim: Int, path: Path): Option[Path] =
-  tour_on_mega_board_aux(dim, List(path))
-
-
-def tour_on_mega_board(dim: Int, path: Path) =
-  time_needed(ttour_on_mega_board(dim: Int, path: Path))
-
-
-// testcases
-//print_board(70, tour_on_mega_board(70, List((0, 0))).get)
-
-
-
-}
-
-
-//val dim = 30 //75
-//M4c.print_board(dim, M4c.tour_on_mega_board(dim, List((0, 0))).get)