1 // Part 2 about finding a single tour for a board

     2 //================================================

     3 

     4 // copy any function you need from file knight1.scala

     5 

     6 object CW7b {

     7 

     8 type Pos = (Int, Int)    // a position on a chessboard 

     9 type Path = List[Pos]    // a path...a list of positions

    10 

    11 

    12 //(2a) Implement a first-function that finds the first 

    13 //     element, say x, in the list xs where f is not None. 

    14 //     In that case Return f(x), otherwise None. If possible,

    15 //     calculate f(x) only once.

    16 

    17 //def first(xs: List[Pos], f: Pos => Option[Path]) : Option[Path] = ...

    18 

    19 //(2b) Implement a function that uses the first-function for

    20 //     trying out onward moves, and searches recursively for a

    21 //     knight tour on a dim * dim-board.

    22 

    23 //def first_tour(dim: Int, path: Path) : Option[Path] = ...

    24  

    25 

    26 }