// Part 3 about finding a single tour using the Warnsdorf Rule
//=============================================================
// copy any function you need from files knight1.scala and
// knight2.scala
object CW7c {
type Pos = (Int, Int)    // a position on a chessboard 
type Path = List[Pos]    // a path...a list of positions
//(3a) Complete the function that calculates a list of onward
//     moves like in (1b) but orders them according to Warnsdorf’s 
//     rule. That means moves with the fewest legal onward moves 
//     should come first.
//def ordered_moves(dim: Int, path: Path, x: Pos) : List[Pos] = ..
//(3b) Complete the function that searches for a single *closed* 
//     tour using the ordered moves function.
//def first_closed_tour_heuristic(dim: Int, path: Path) : Option[Path] = ...
//(3c) Same as (3b) but searches for *non-closed* tours. However, 
//     you have to be careful to write a tail-recursive version as this 
//     function will be called with dimensions of up to 40 * 40.
//def first_tour_heuristic(dim: Int, path: Path) : Option[Path] = ...
}