day 9 puzzle 1

This commit is contained in:
2023-12-09 11:53:51 +01:00
parent 76427545d6
commit c3c9a8a4e4
5 changed files with 85 additions and 2 deletions

41
src/day9/Puzzle1.scala Normal file
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package day9
import scala.collection.mutable
import scala.io.{BufferedSource, Source}
import scala.util.matching.Regex
import scala.util.matching.Regex.Match
object Puzzle1 {
var series: Array[Series] = Array.empty
def loadInput(path: String): Unit = {
val source: BufferedSource = Source.fromFile(path)
val lines: Array[String] = source.getLines().toArray
series = new Array(lines.length)
for ((line: String, i: Int) <- lines.zipWithIndex) {
series(i) = new Series(line.split(" ").map(_.toInt))
}
source.close()
}
def solve(path: String): Int = {
loadInput(path)
var solution: Int = 0
for (s: Series <- series) {
s.computeDiffs()
solution += s.extrapolate()
}
return solution
}
def main(args: Array[String]): Unit = {
val solution: Int = solve("./res/day9/input1.txt")
println(solution)
}
}

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src/day9/Series.scala Normal file
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package day9
import scala.collection.mutable.ArrayBuffer
class Series {
private val values: ArrayBuffer[Array[Int]] = new ArrayBuffer()
def this(initialValues: Array[Int]) = {
this()
values.addOne(initialValues.concat(Array(0)))
}
def computeDiffs(): Unit = {
while (!(values.last.dropRight(1).distinct.length == 1 && values.last(0) == 0)) {
val diffs: Array[Int] = new Array(values.last.length-1)
for (i: Int <- 0 until diffs.length-1) {
diffs(i) = values.last(i+1) - values.last(i)
}
values.addOne(diffs)
}
}
def extrapolate(): Int = {
val len: Int = values(0).length
values.last(values.last.length-1) = 0
for (i: Int <- values.length-2 to 0 by -1) {
values(i)(len-i-1) = values(i)(len-i-2) + values(i+1)(len-i-2)
}
return values(0).last
}
}