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codeforkjeffcodeforkjeff
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reorg day 9 in prep for part 2
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3 files changed

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‎src/main/scala/org/codefork/aoc2018/Day9.scala

Lines changed: 84 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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package org.codefork.aoc2018
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import scala.annotation.tailrec
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import scala.io.Source
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object Day9 {
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case class Game(numPlayers: Int, lastMarblePoints: Int) {
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def findHighestScore: Int = calculateFinalScores().values.max
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// player is 0-indexed instead of 1-indexed as in example
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@tailrec
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final def calculateFinalScores(player: Int = 0,
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circle: Vector[Int] = Vector(0),
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indexOfCurrentMarble: Int = 0,
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marbleCounter: Int = 0,
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scores: Map[Int, Int] = Map.empty,
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lastScore: Int = -1): Map[Int, Int] = {
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if (marbleCounter == lastMarblePoints) {
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scores
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} else {
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val nextPlayer = (player + 1) % numPlayers
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val toPlace = marbleCounter + 1
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if (toPlace % 23 == 0) {
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val indexToRemove = {
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val minus7 = indexOfCurrentMarble - 7
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if (minus7 < 0) minus7 + circle.size else minus7
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}
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val score = toPlace + circle(indexToRemove)
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val newScores = scores + (player -> (scores.getOrElse(player, 0) + score))
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val newCircle = circle.patch(indexToRemove, List.empty, 1)
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println("player " + player + " scored " + score + " with marble " + toPlace)
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println("index at -7 = " + indexToRemove + ", marble = " + circle(indexToRemove) + " newCurrent=" + newCircle(indexToRemove))
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//println(player, newCircle)
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// "The marble located immediately clockwise of the marble
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// that was removed becomes the new current marble."
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calculateFinalScores(nextPlayer,
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newCircle,
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indexToRemove,
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marbleCounter + 1,
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newScores,
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score)
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} else {
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// this inserts at start of list instead of at end, so it looks diff from example
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// on website, but it's effectively the same thing
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val indexToInsert =
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if (circle.size == 1) 1
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else (indexOfCurrentMarble + 2) % circle.size
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val newCircle = circle.patch(indexToInsert, Seq(toPlace), 0)
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//println(player, newCircle)
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calculateFinalScores(nextPlayer,
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newCircle,
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indexToInsert,
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marbleCounter + 1,
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scores)
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}
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}
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}
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}
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//val getTestData = "9 players; last marble is worth 32 points"
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//val getTestData = "10 players; last marble is worth 1618 points"
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//val getTestData = "13 players; last marble is worth 7999 points"
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val getInputData = {
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val url = getClass.getResource("/day9/input.txt")
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Source.fromURL(url).mkString.stripLineEnd
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}
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}

‎src/main/scala/org/codefork/aoc2018/Day9Part1.scala

Lines changed: 2 additions & 81 deletions
Original file line numberDiff line numberDiff line change
@@ -1,91 +1,12 @@
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package org.codefork.aoc2018
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import scala.annotation.tailrec
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import scala.io.Source
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object Day9Part1 extends Part {
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case class Game(numPlayers: Int, lastMarblePoints: Int) {
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def findHighestScore: Int = calculateFinalScores().values.max
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// player is 0-indexed instead of 1-indexed as in example
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@tailrec
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final def calculateFinalScores(player: Int = 0,
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circle: Vector[Int] = Vector(0),
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indexOfCurrentMarble: Int = 0,
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marbleCounter: Int = 0,
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scores: Map[Int, Int] = Map.empty,
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lastScore: Int = -1): Map[Int, Int] = {
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if (marbleCounter == lastMarblePoints) {
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scores
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} else {
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val nextPlayer = (player + 1) % numPlayers
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val toPlace = marbleCounter + 1
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if (toPlace % 23 == 0) {
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val indexToRemove = {
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val minus7 = indexOfCurrentMarble - 7
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if (minus7 < 0) minus7 + circle.size else minus7
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}
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val score = toPlace + circle(indexToRemove)
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val newScores = scores + (player -> (scores.getOrElse(player, 0) + score))
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val newCircle = circle.patch(indexToRemove, List.empty, 1)
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//println(player + " scored " + score)
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//println("marble at -7 was " + circle(indexToRemove))
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//println(player, newCircle)
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// "The marble located immediately clockwise of the marble
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// that was removed becomes the new current marble."
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calculateFinalScores(nextPlayer,
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newCircle,
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indexToRemove,
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marbleCounter + 1,
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newScores,
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score)
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} else {
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// this inserts at start of list instead of at end, so it looks diff from example
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// on website, but it's effectively the same thing
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val indexToInsert =
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if (circle.size == 1) 1
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else (indexOfCurrentMarble + 2) % circle.size
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val newCircle = circle.patch(indexToInsert, Seq(toPlace), 0)
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//println(player, newCircle)
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calculateFinalScores(nextPlayer,
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newCircle,
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indexToInsert,
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marbleCounter + 1,
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scores)
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}
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}
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}
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}
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//val getTestData = "9 players; last marble is worth 32 points"
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//val getTestData = "10 players; last marble is worth 1618 points"
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//val getTestData = "13 players; last marble is worth 7999 points"
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val getInputData = {
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val url = getClass.getResource("/day9/input.txt")
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Source.fromURL(url).mkString.stripLineEnd
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}
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override def answer: String = {
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//val input = getTestData
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val input = getInputData
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val input = Day9.getInputData
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val matches = raw"\d+".r.findAllMatchIn(input).toList.map(_.toString.toInt)
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Game(matches(0), matches(1)).findHighestScore.toString
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Day9.Game(matches(0), matches(1)).findHighestScore.toString
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}
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}

‎src/main/scala/org/codefork/aoc2018/Main.scala

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,7 +18,8 @@ object Main {
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Day7Part1,
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Day7Part2,
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Day8Part1,
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Day8Part2
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Day8Part2,
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Day9Part1
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)
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def main(args: Array[String]) = {

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