Bye bye sbt

aoc/src/main/scala/dev/ctsk/aoc/Main.scala

@@ -0,0 +1,19 @@
+package dev.ctsk.aoc
+
+import dev.ctsk.aoc.days._
+
+val solvers = Map[Int, Solver](
+  1 -> Day01,
+  2 -> Day02
+)
+
+@main def main(day: String, input: String): Unit =
+  solvers.get(day.toInt) match
+    case Some(solver) =>
+      val (timings, solution) = solver.run(input)
+      println(f"Preprocessing: ${timings.prep}%24s μs")
+      println(f"Part 1: ${solution.p1}%15s ${timings.p1}%15s μs")
+      println(f"Part 2: ${solution.p2}%15s ${timings.p2}%15s μs")
+
+    case None =>
+      println(s"Day $day not solved")

aoc/src/main/scala/dev/ctsk/aoc/Solution.scala

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+package dev.ctsk.aoc
+
+case class Timings(prep: Long, p1: Long, p2: Long)
+
+case class Solution(p1: Object, p2: Object)
+
+abstract class Solver(day: Int):
+  def run(input: String): (Timings, Solution)
+
+  def timed[A](solution: => A): (Long, A) =
+    val start = System.nanoTime()
+    val result = solution
+    val end = System.nanoTime()
+
+    ((end - start) / 1000, result)

aoc/src/main/scala/dev/ctsk/aoc/days/Day01.scala

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+package dev.ctsk.aoc.days
+
+import dev.ctsk.aoc._
+
+object Day01 extends Solver(1):
+  type Input = (Array[Int], Array[Int])
+
+  def pre(input: String): Input =
+    io.Source
+      .fromFile(input)
+      .getLines()
+      .map { case s"$i   $j" => (i.toInt, j.toInt) }
+      .toArray
+      .unzip match { case (left, right) => (left.sorted, right.sorted) }
+
+  def part1(input: Input): Int =
+    input match
+      case (left, right) => left.zip(right).map(_ - _).map(_.abs).sum
+
+  def part2(input: Input): Int =
+    val (left, right) = input;
+    val counts = right.groupMapReduce(identity)(identity)(_ + _)
+    left.map(n => counts.getOrElse(n, 0)).sum
+
+  def run(input: String): (Timings, Solution) =
+    val (pre_time, pre_input) = timed { pre(input) }
+    val (p1_time, p1_solution) = timed { part1(pre_input) }
+    val (p2_time, p2_solution) = timed { part2(pre_input) }
+
+    (
+      Timings(pre_time, p1_time, p2_time),
+      Solution(Int.box(p1_solution), Int.box(p2_solution))
+    )

aoc/src/main/scala/dev/ctsk/aoc/days/Day02.scala

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+package dev.ctsk.aoc.days
+
+import dev.ctsk.aoc._
+
+object Day02 extends Solver(2):
+  def pre(input: String): List[List[Int]] =
+    io.Source
+      .fromFile(input)
+      .getLines()
+      .map(line => line.split(" ").map(_.toInt).toList)
+      .toList
+
+  def safe(list: List[Int]): Boolean =
+    list.length < 2 || list
+      .sliding(2)
+      .collect { case List(a, b) => b - a }
+      .forall(1 to 3 contains _)
+
+  def safeWithGap(list: List[Int]): Boolean =
+    list.indices.exists(i => safe(list.take(i) ++ list.drop(i + 1)))
+
+  def part1(lists: List[List[Int]]): Int =
+    lists.count(list => safe(list) || safe(list.reverse))
+
+  def part2(lists: List[List[Int]]): Int =
+    lists.count(list => safeWithGap(list) || safeWithGap(list.reverse))
+
+  def run(input: String): (Timings, Solution) =
+    val (pre_time, pre_input) = timed { pre(input) }
+    val (p1_time, p1_solution) = timed { part1(pre_input) }
+    val (p2_time, p2_solution) = timed { part2(pre_input) }
+
+    (
+      Timings(pre_time, p1_time, p2_time),
+      Solution(Int.box(p1_solution), Int.box(p2_solution))
+    )