day2

input/2021/day2-sample1.txt

@@ -0,0 +1,6 @@
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2

src/main/scala/de.qwertyuiop.aoc/2021/day2.scala

@@ -3,4 +3,26 @@ package de.qwertyuiop.aoc.`2021`
 import de.qwertyuiop.aoc.lib.*
 import cats.*, cats.implicits.given
 
-def day2(using InputSource): Unit = ???
+import Vectors.*
+
+def day2(using InputSource): Unit =
+  val commands = input()
+  println(simpleCommands(commands))
+  println(aimCommands(commands))
+
+
+def simpleCommands(commands: List[String]) =
+  val finalPos = commands.map{
+    case s"forward $x" => Vec2D(x.toInt, 0)
+    case s"down $y" => Vec2D(0, y.toInt)
+    case s"up $y" => Vec2D(0, - y.toInt)
+  }.combineAll
+  s"(1) Final position: ${finalPos}\nResult: ${finalPos.x * finalPos.y}"
+
+def aimCommands(commands: List[String]) =
+  val finalPos = commands.map{
+    case s"forward $x" => Vec3D(x.toInt, x.toInt, 0)
+    case s"down $aim" => Vec3D(0, 0, aim.toInt)
+    case s"up $aim" => Vec3D(0, 0, - aim.toInt)
+  }.foldLeft(Vec3D(0,0,0))((pos, command) => Vec3D(pos.x + command.x, pos.y + pos.z * command.y, pos.z + command.z))
+  s"(2) Final position: ${finalPos}\nResult: ${finalPos.x * finalPos.y}"