Project Euler Problem 49

gistfile1.scala

import scala.collection.mutable

val bs = mutable.BitSet( (2 to 9999): _*)

var cur = 2
while(cur * cur <= 9999) {
  if(bs(cur)) {
    var mul = 2 * cur
    while(mul <= 9999) {
      bs -= mul
      mul += cur
    }
  }

  cur += 1
}

for(first <- 1000 to 9999) {
  val stream = Stream.iterate(first) { _ + 3330 } takeWhile { _ <= 9999 }
  if( stream.size >= 3 && stream.forall(bs.apply) ) {
    if( stream.map { number => number.toString.foldLeft(Map.empty[Char, Int].withDefaultValue(0)) {
      (m, c) => m.updated(c, m(c) + 1) } }.toSet.size == 1)
      println(stream.mkString)
  }
}