Day 3

aoc/src/Day3.scala

@@ -0,0 +1,30 @@
+import scala.io.Source
+
+object Day3 extends App:
+
+  val input = Source
+    .fromURL(getClass.getResource("day3Input.txt"))
+    .mkString
+    .split('\n')
+    .toList
+
+  val part1 = input
+    .map(rucksack => rucksack.splitAt(rucksack.length / 2))
+    .map(rucksack => rucksack._1.toSet.intersect(rucksack._2.toSet))
+    .map(_.map(computePriority).sum)
+    .sum
+
+  def computePriority(char: Char): Int =
+    if char.isUpper then char - 38
+    else char - 96
+
+  println(s"Part 1: $part1")
+
+  val part2 = input
+    .map(_.toSet)
+    .grouped(3)
+    .map(_.reduce(_.intersect(_)))
+    .map(_.map(computePriority).sum)
+    .sum
+
+  println(s"Part 2: $part2")