8面ダイスの各面の割り当てを試す

Dice8.scala

package dice

class Dice8(num: IndexedSeq[Int]) {
  def this(n0: Int, n1: Int, n2: Int, n3: Int) = {
    this(Array(n0, n1, n2, n3, 9 - n2, 9 - n3, 9 - n0, 9 - n1))
  }

  private val 隣接 = Array(
    Array(1, 3, 4), //0
    Array(0, 5, 2), //1
    Array(1, 6, 3), //2
    Array(0, 2, 7), //3
    Array(0, 7, 5), //4
    Array(4, 6, 1), //5
    Array(5, 7, 2), //6
    Array(4, 3, 6)) //7

  def ばらつき度: Int = {
    隣接.zipWithIndex.map {
      case (a, i) => a.map(j => num(j) - num(i)).map(m => m * m).sum
    }.sum
  }

  override def toString() = num.mkString("Dice8(", ",", ")")

  def print(): Unit = {
    printf("＼%2d／%n", num(2))
    printf("%2d×%2d%n", num(3), num(1))
    printf("／%2d＼%n", num(0))
    printf("＼%2d／%n", num(6))
    printf("%2d×%2d%n", num(7), num(5))
    printf("／%2d＼%n", num(4))
    println
  }
}

object Dice8 {
  private val N = 1 + 8

  def main(args: Array[String]) {
    check()
    println("-" * 32)
    checkAll()
  }

  //ある面と裏の面との合計が一定のパターンだけ試す
  def check() {
    val seq = Seq(2, 3, 4)
    check(1, seq)
  }
  def check(n0: Int, ns: Seq[Int]) {
    for (n <- ns) {
      val seq = ns.filter(_ != n)
      check(n0, n, seq)
      check(n0, N - n, seq)
    }
  }
  def check(n0: Int, n1: Int, ns: Seq[Int]) {
    val n2 = ns.head
    val n3 = ns.last
    check(n0, n1, n2, n3)
    check(n0, n1, n2, N - n3)
    check(n0, n1, N - n2, n3)
    check(n0, n1, N - n2, N - n3)
  }
  def check(n0: Int, n1: Int, n2: Int, n3: Int) {
    val d = new Dice8(n0, n1, n2, n3)
    val s = d.ばらつき度
    if (s > 400 || s < 170) {
      printf("%s\t%d%n", d, s)
      d.print()
    }
  }

  //全パターンを試す
  def checkAll() {
    for (ns <- (2 to 8).permutations) { //順列組み合わせ
      checkAll(1 +: ns)
    }
  }
  def checkAll(ns: IndexedSeq[Int]) {
    val d = new Dice8(ns)
    val s = d.ばらつき度
    if (s > 460 /*|| s < 170*/ ) {
      printf("%s\t%d%n", d, s)
      d.print()
    }
  }
}

このプログラムを作ろうと思った経緯
http://blog.goo.ne.jp/hishidama/e/b85eb67ffee0fe9333d8e39020b4625f