1 

     2 //import scala.concurrent._

     3 //import scala.concurrent.duration._

     4 //import ExecutionContext.Implicits.global

     5 //import scala.language.postfixOps 

     6 

     7 type Pos = (Int, Int)

     8 type Path = List[Pos]

     9 

    10 def add_pair_urban(x: Pos)(y: Pos): Pos = 

    11   (x._1 + y._1, x._2 + y._2)

    12 

    13 def is_legal_urban(dim: Int, path: Path)(x: Pos): Boolean = 

    14   0 <= x._1 && 0 <= x._2 && x._1 < dim && x._2 < dim && !path.contains(x)

    15 

    16 def moves_urban(x: Pos): List[Pos] = 

    17   List(( 1,  2),( 2,  1),( 2, -1),( 1, -2),

    18        (-1, -2),(-2, -1),(-2,  1),(-1,  2)).map(add_pair_urban(x))

    19 

    20 def legal_moves_urban(dim: Int, path: Path, x: Pos): List[Pos] = 

    21   moves_urban(x).filter(is_legal_urban(dim, path))

    22 

    23 def correct_urban(dim: Int)(p: Path): Boolean = p match {

    24   case Nil => true

    25   case x::Nil => true

    26   case x::y::p => 

    27     if (legal_moves_urban(dim, p, y).contains(x)) correct_urban(dim)(y::p) else false

    28 }

    29 

    30 //lazy val f1 = Future {

    31 

    32   val ts8 = CW7c.first_tour_heuristic(8, List((0,0))).get

    33   assert(correct_urban(8)(ts8) == true)

    34 

    35 //}

    36 

    37 //Await.result(f1, 360 second)

    38 

    39 

    40 //lazy val f2 = Future {

    41 

    42   val ts40 = CW7c.first_tour_heuristic(40, List((0,0))).get

    43   assert(correct_urban(40)(ts40) == true)

    44 

    45 //}

    46 

    47 //Await.result(f2, 360 second)