Day 03

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

@@ -4,7 +4,8 @@ import dev.ctsk.aoc.days._
 
 val solvers = Map[Int, Solver](
   1 -> Day01,
-  2 -> Day02
+  2 -> Day02,
+  3 -> Day03
 )
 
 @main def main(day: String, input: String): Unit =

aoc/src/main/scala/dev/ctsk/aoc/days/Day03.scala

@@ -0,0 +1,34 @@
+package dev.ctsk.aoc.days
+
+import dev.ctsk.aoc._
+
+object Day03 extends Solver(3):
+  def mul(segment: String): Int =
+    segment.substring(4, segment.length - 1).split(",").map(_.toInt).product
+
+  def part1(input: String): Int =
+    val pattern = """mul\(\d{1,3},\d{1,3}\)""".r
+    pattern.findAllIn(input).toList.map(mul).sum
+
+  def part2(line: String): Int =
+    val pattern = """(mul\(\d{1,3},\d{1,3}\))|do\(\)|don't\(\)""".r;
+
+    pattern
+      .findAllIn(line)
+      .foldLeft((true, 0)) { case ((enabled, sum), curr) =>
+        curr match
+          case "do()"    => (true, sum)
+          case "don't()" => (false, sum)
+          case _         => (enabled, if enabled then sum + mul(curr) else sum)
+      }
+      ._2
+
+  def run(input: String): (Timings, Solution) =
+    val in = io.Source.fromFile(input).mkString
+    val (p1_time, p1_solution) = timed { part1(in) }
+    val (p2_time, p2_solution) = timed { part2(in) }
+
+    (
+      Timings(0, p1_time, p2_time),
+      Solution(Int.box(p1_solution), Int.box(p2_solution))
+    )