1 

     2 

     3 def print_board(n: Int)(steps: List[(Int, Int)]): Unit = {

     4   for (i <- 0 until n) {

     5     for (j <- 0 until n) {

     6       print(f"${steps.indexOf((i, j))}%2.0f ")

     7     }

     8     println

     9   } 

    10   //readLine()

    11   System.exit(0)

    12 }

    13 

    14 def add_pair(x: (Int, Int))(y: (Int, Int)) = 

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

    16 

    17 def is_legal(n: Int)(x: (Int, Int)) = 

    18   0 <= x._1 && 0 <= x._2 && x._1 < n && x._2 < n

    19 

    20 def moves(n: Int)(x: (Int, Int)): List[(Int, Int)] = {

    21   Set((1, 2),(2, 1),(2, -1),(1, -2),

    22       (-1, -2),(-2, -1),(-2, 1),(-1, 2)).map(add_pair(x)).filter(is_legal(n))

    23 }

    24 

    25 def tour(n: Int)(steps: List[(Int, Int)]): Unit = {

    26   if (steps.length ==  n * n && moves(n)(steps.head).contains(steps.last))

    27     print_board(n)(steps)

    28   else 

    29     for (x <- moves(n)(steps.head).par; if (!steps.contains(x))) tour(n)(x :: steps)

    30 }

    31 

    32 val n = 6

    33 

    34 println("started")

    35 for (i <- 0 until n; j <- 0 until n) tour(n)(List((i, j)))

    36 println("finished")