shkesar · April 10, 2016 18:25
diff --git a/NQueen.scala b/NQueen.scala
 def nQueens(n: Int) = (0 until n).permutations filter {p => 
  val i = p.zipWithIndex.toSet              // p[i] is the column of the queen on ith row (must be a permutation of 0 until n)
  i.map{case (c, d) => c + d}.size == n &&  // No 2 queens can have same col + diag
  i.map{case (c, d) => c - d}.size == n     // No 2 queens can have same col - diag
 }

 for {
  (solution, num) <- nQueens(8).zipWithIndex
  _ = println(s"Solution #${num + 1}:")
  col <- solution
  row = solution.indices.map(i => if (i == col) 'Q' else '-')
 } println(row.mkString)
	def nQueens(n: Int) = (0 until n).permutations filter {p =>
	val i = p.zipWithIndex.toSet // p[i] is the column of the queen on ith row (must be a permutation of 0 until n)
	i.map{case (c, d) => c + d}.size == n && // No 2 queens can have same col + diag
	i.map{case (c, d) => c - d}.size == n // No 2 queens can have same col - diag
	}

	for {
	(solution, num) <- nQueens(8).zipWithIndex
	_ = println(s"Solution #${num + 1}:")
	col <- solution
	row = solution.indices.map(i => if (i == col) 'Q' else '-')
	} println(row.mkString)