Project Euler Problem 4

problem4.scala

  /**
   * http://projecteuler.net/problem=4
   * http://odz.sakura.ne.jp/projecteuler/index.php?cmd=read&page=Problem%204
   */
  val xs = List.range(999, 99, - 1)
  val ys = List.range(999, 99, - 1)

  val isPalindromicNumber = (n: Int) => {
    n.toString == n.toString.reverse
  }

  val ret = xs.map{ x =>
    ys.map(y => if (isPalindromicNumber(x * y)) x * y else 0).max
  }.max

  println(ret)