diff -r 19b75e899d37 -r 9c03b5e89a2a assignment2021scala/main4/knight1.scala
--- a/assignment2021scala/main4/knight1.scala	Fri Apr 26 17:29:30 2024 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,109 +0,0 @@
-// Main Part 4 about finding Knight's tours
-//==========================================
-
-
-object M4a {
-
-// If you need any auxiliary functions, feel free to 
-// implement them, but do not make any changes to the
-// templates below. Also have a look whether the functions
-// at the end of the file are of any help.
-
-
-
-type Pos = (Int, Int)    // a position on a chessboard 
-type Path = List[Pos]    // a path...a list of positions
-
-//(1) Complete the function that tests whether the position x
-//    is inside the board and not yet element in the path.
-
-def is_legal(dim: Int, path: Path, x: Pos) : Boolean = ???
-
-
-
-//(2) Complete the function that calculates for a position x
-//    all legal onward moves that are not already in the path. 
-//    The moves should be ordered in a "clockwise" manner.
- 
-def legal_moves(dim: Int, path: Path, x: Pos) : List[Pos] = ???
-
-
-//some testcases
-//
-//assert(legal_moves(8, Nil, (2,2)) == 
-//  List((3,4), (4,3), (4,1), (3,0), (1,0), (0,1), (0,3), (1,4)))
-//assert(legal_moves(8, Nil, (7,7)) == List((6,5), (5,6)))
-//assert(legal_moves(8, List((4,1), (1,0)), (2,2)) == 
-//  List((3,4), (4,3), (3,0), (0,1), (0,3), (1,4)))
-//assert(legal_moves(8, List((6,6)), (7,7)) == List((6,5), (5,6)))
-
-
-//(3) Complete the two recursive functions below. 
-//    They exhaustively search for knight's tours starting from the 
-//    given path. The first function counts all possible tours, 
-//    and the second collects all tours in a list of paths.
-
-def count_tours(dim: Int, path: Path) : Int = ???
-
-def enum_tours(dim: Int, path: Path) : List[Path] = ???
-
-
-//(4) Implement a first-function that finds the first 
-//    element, say x, in the list xs where f is not None. 
-//    In that case Return f(x), otherwise None. If possible,
-//    calculate f(x) only once.
-
-def first(xs: List[Pos], f: Pos => Option[Path]) : Option[Path] = ???
-
-
-// testcases
-//
-//def foo(x: (Int, Int)) = if (x._1 > 3) Some(List(x)) else None
-//
-//first(List((1, 0),(2, 0),(3, 0),(4, 0)), foo)   // Some(List((4,0)))
-//first(List((1, 0),(2, 0),(3, 0)), foo)          // None
-
-
-//(5) Implement a function that uses the first-function from (4) for
-//    trying out onward moves, and searches recursively for a
-//    knight tour on a dim * dim-board.
-
-def first_tour(dim: Int, path: Path) : Option[Path] = ???
- 
-
-
-/* Helper functions
-
-
-// for measuring time
-def time_needed[T](code: => T) : T = {
-  val start = System.nanoTime()
-  val result = code
-  val end = System.nanoTime()
-  println(f"Time needed: ${(end - start) / 1.0e9}%3.3f secs.")
-  result
-}
-
-// can be called for example with
-//
-//     time_needed(count_tours(dim, List((0, 0))))
-//
-// in order to print out the time that is needed for 
-// running count_tours
-
-
-// for printing a board
-def print_board(dim: Int, path: Path): Unit = {
-  println()
-  for (i <- 0 until dim) {
-    for (j <- 0 until dim) {
-      print(f"${path.reverse.indexOf((j, dim - i - 1))}%3.0f ")
-    }
-    println()
-  } 
-}
-
-
-*/
-
-}