Scalaで8-queens ref: http://qiita.com/takaki@github/items/d0c8b53b678d359922a1

file0.scala

object EightQueens {

  def queen(n: Int): List[List[Int]] = n match {
    case 0 => List(List())
    case `n` => for {b <- queen(n - 1); q <- 0 to 7 if safe(q, b)} yield q :: b
  }

  def safe(q: Int, b: List[Int]) = b.indices.forall(i => checks(q, b, i))

  def checks(q: Int, b: List[Int], i: Int) = q != b(i) && (Math.abs(q - b(i)) != i + 1)

  def main(args: Array[String]) {
    val res = queen(8)
    res.foreach(l => println(l))
    println(res.length)
  }

}