day 11 puzzle 2

README.md

@@ -5,11 +5,11 @@ This repo contains my attempt at this year's Advent of Code (2023)
 I will try and do some problems (probably not all of them) in Scala
 
 ## Progress:
-#### Stars: 21 / 50
+#### Stars: 22 / 50
 |        Mon         |        Tue        |        Wed        |        Thu        |        Fri        |        Sat        |        Sun         |
-|:-----------------:|:-----------------:|:-----------------:|:-----------------:|:-----------------:|:-----------------:|:------------------:|
+|:------------------:|:-----------------:|:-----------------:|:-----------------:|:-----------------:|:-----------------:|:------------------:|
 |                    |                   |                   |                   | 1<br>:star::star: | 2<br>:star::star: | 3<br>:star::star:  |
 | 4<br>:star::star:  | 5<br>:star::star: | 6<br>:star::star: | 7<br>:star::star: | 8<br>:star::star: | 9<br>:star::star: | 10<br>:star::star: |
-|   11<br>:star:    |        12         |        13         |        14         |        15         |        16         |         17         |
+| 11<br>:star::star: |        12         |        13         |        14         |        15         |        16         |         17         |
 |         18         |        19         |        20         |        21         |        22         |        23         |         24         |
 |         25         |                   |                   |                   |                   |                   |                    |

src/day11/Puzzle2.scala

@@ -0,0 +1,82 @@
+package day11
+
+import scala.collection.mutable.ArrayBuffer
+import scala.io.{BufferedSource, Source}
+
+object Puzzle2 {
+  var ogUniverse: Array[Array[Boolean]] = Array.empty
+  var ogHeight: Int = 0
+  var ogWidth: Int = 0
+  var colCounts: Array[Int] = Array.empty
+  var rowCounts: Array[Int] = Array.empty
+  var galaxies: ArrayBuffer[(Long, Long)] = new ArrayBuffer()
+  def loadInput(path: String): Unit = {
+    val source: BufferedSource = Source.fromFile(path)
+    val lines: Array[String] = source.getLines().toArray
+
+    ogHeight = lines.length
+    ogWidth = if (ogHeight == 0) 0 else lines(0).length
+    ogUniverse = Array.ofDim(ogHeight, ogWidth)
+
+    colCounts = new Array(ogWidth)
+    rowCounts = new Array(ogHeight)
+
+    for ((line: String, y: Int) <- lines.zipWithIndex) {
+      for ((c: Char, x: Int) <- line.zipWithIndex) {
+        if (c == '#') {
+          ogUniverse(y)(x) = true
+          colCounts(x) += 1
+          rowCounts(y) += 1
+        }
+      }
+    }
+
+    source.close()
+  }
+
+  def findGalaxiesRealPos(age: Int): Unit = {
+    galaxies = new ArrayBuffer()
+
+    var realX: Long = 0
+    var realY: Long = 0
+
+    for (ogY: Int <- 0 until ogHeight) {
+      realX = 0
+      for (ogX: Int <- 0 until ogWidth) {
+        if (ogUniverse(ogY)(ogX)) {
+          galaxies.addOne((realX, realY))
+        }
+        if (colCounts(ogX) == 0) realX += age-1
+        realX += 1
+      }
+      if (rowCounts(ogY) == 0) realY += age-1
+      realY += 1
+    }
+  }
+
+  def distance(g1: (Long, Long), g2: (Long, Long)): Long = {
+    return Math.abs(g2._1 - g1._1) + Math.abs(g2._2 - g1._2)
+  }
+
+  def solve(path: String, age: Int=2): Long = {
+    loadInput(path)
+    findGalaxiesRealPos(age)
+
+    var solution: Long = 0
+
+    for (i: Int <- galaxies.indices) {
+      val g1: (Long, Long) = galaxies(i)
+      for (j: Int <- i+1 until galaxies.length) {
+        val g2: (Long, Long) = galaxies(j)
+        solution += distance(g1, g2)
+      }
+    }
+
+    return solution
+  }
+
+  def main(args: Array[String]): Unit = {
+    val solution: Long = solve("./res/day11/input1.txt", 1000000)
+    println(solution)
+  }
+}

tests/day11/Puzzle2Test.scala

@@ -0,0 +1,12 @@
+package day11
+
+import org.scalatest.funsuite.AnyFunSuite
+
+class Puzzle2Test extends AnyFunSuite {
+  test("Puzzle2.solve 1") {
+    assert(Puzzle2.solve("tests_res/day11/input1.txt", 10) == 1030)
+  }
+  test("Puzzle2.solve 2") {
+    assert(Puzzle2.solve("tests_res/day11/input1.txt", 100) == 8410)
+  }
+}