samskivert: Euler 008

09 January 2008

Problem 008\:

object Euler8 extends Application {
  val number = ("73167176531330624919225119674426574742355349194934" +
                "96983520312774506326239578318016984801869478851843" +
                "85861560789112949495459501737958331952853208805511" +
                "12540698747158523863050715693290963295227443043557" +
                "66896648950445244523161731856403098711121722383113" +
                "62229893423380308135336276614282806444486645238749" +
                "30358907296290491560440772390713810515859307960866" +
                "70172427121883998797908792274921901699720888093776" +
                "65727333001053367881220235421809751254540594752243" +
                "52584907711670556013604839586446706324415722155397" +
                "53697817977846174064955149290862569321978468622482" +
                "83972241375657056057490261407972968652414535100474" +
                "82166370484403199890008895243450658541227588666881" +
                "16427171479924442928230863465674813919123162824586" +
                "17866458359124566529476545682848912883142607690042" +
                "24219022671055626321111109370544217506941658960408" +
                "07198403850962455444362981230987879927244284909188" +
                "84580156166097919133875499200524063689912560717606" +
                "05886116467109405077541002256983155200055935729725" +
                "71636269561882670428252483600823257530420752963450");
  val WINDOW = 5;
  def prod5 (offset :Int) :Int = {
    number.slice(offset, offset+WINDOW).toList.map((c) => (c - '0')).foldLeft(1)(_*_)
  }
  println(List.range(0, number.length-WINDOW).foldRight(0)((o, g) => (Math.max(g, prod5(o)))))
}

I'll stop here for tonight. I already have solutions up to Problem 30, but I'll try to restrict myself to posting a few at a time so as not to try the patience of my already very kind and indulgent readers.

©1999–2013 Michael Bayne