day 9 puzzle 1
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41
src/day9/Puzzle1.scala
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41
src/day9/Puzzle1.scala
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package day9
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import scala.collection.mutable
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import scala.io.{BufferedSource, Source}
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import scala.util.matching.Regex
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import scala.util.matching.Regex.Match
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object Puzzle1 {
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var series: Array[Series] = Array.empty
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def loadInput(path: String): Unit = {
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val source: BufferedSource = Source.fromFile(path)
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val lines: Array[String] = source.getLines().toArray
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series = new Array(lines.length)
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for ((line: String, i: Int) <- lines.zipWithIndex) {
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series(i) = new Series(line.split(" ").map(_.toInt))
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}
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source.close()
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}
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def solve(path: String): Int = {
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loadInput(path)
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var solution: Int = 0
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for (s: Series <- series) {
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s.computeDiffs()
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solution += s.extrapolate()
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}
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return solution
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}
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def main(args: Array[String]): Unit = {
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val solution: Int = solve("./res/day9/input1.txt")
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println(solution)
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}
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}
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30
src/day9/Series.scala
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30
src/day9/Series.scala
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package day9
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import scala.collection.mutable.ArrayBuffer
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class Series {
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private val values: ArrayBuffer[Array[Int]] = new ArrayBuffer()
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def this(initialValues: Array[Int]) = {
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this()
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values.addOne(initialValues.concat(Array(0)))
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}
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def computeDiffs(): Unit = {
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while (!(values.last.dropRight(1).distinct.length == 1 && values.last(0) == 0)) {
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val diffs: Array[Int] = new Array(values.last.length-1)
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for (i: Int <- 0 until diffs.length-1) {
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diffs(i) = values.last(i+1) - values.last(i)
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}
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values.addOne(diffs)
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}
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}
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def extrapolate(): Int = {
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val len: Int = values(0).length
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values.last(values.last.length-1) = 0
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for (i: Int <- values.length-2 to 0 by -1) {
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values(i)(len-i-1) = values(i)(len-i-2) + values(i+1)(len-i-2)
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}
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return values(0).last
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}
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}
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