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43 lines
1.3 KiB
Scala
43 lines
1.3 KiB
Scala
import scala.io.StdIn.readInt
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case class Turn(recipes: Vector[Int], idx1: Int, idx2: Int, turnNb: Int) {
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def newScores(a: Int, b: Int): Vector[Int] =
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(a + b).toString.map(_.toInt - '0').toVector
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def next: Turn = {
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val newRecipes = recipes ++ newScores(recipes(idx1), recipes(idx2))
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val newIdx1 = (idx1 + (newRecipes(idx1) + 1)) % newRecipes.size
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val newIdx2 = (idx2 + (newRecipes(idx2) + 1)) % newRecipes.size
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Turn(newRecipes, newIdx1, newIdx2, turnNb + 1)
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}
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override def toString: String =
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recipes.zipWithIndex.map {
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case (v, k) => k match {
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case _ if k == idx1 => s"($v)"
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case _ if k == idx2 => s"[$v]"
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case _ => s" $v "
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}
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}.mkString(" ")
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def computeScoreAt(n: Int): Option[String] =
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recipes match {
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case _ if recipes.size < n + 10 => None
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case _ => Some(recipes.slice(n, n + 10).mkString(""))
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}
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}
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val input = readInt
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val turn0 = Turn(Vector(3, 7), 0, 1, 0)
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val endTurn = Iterator.iterate(turn0)(_.next)
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.filter(_.recipes.length >= input + 11)
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.next
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// println(s"Score: ${endTurn.computeScoreAt(5)} - Expected: 0124515891")
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// println(s"Score: ${endTurn.computeScoreAt(18)} - Expected: 9251071085")
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// println(s"Score: ${endTurn.computeScoreAt(2018)} - Expected: 5941429882")
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println(s"Score: ${endTurn.computeScoreAt(input).get}")
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