Day 7

aoc/src/Day7.scala

@@ -0,0 +1,35 @@
+import scala.io.Source
+import scala.collection.mutable
+
+object Day7 extends App:
+
+  val input = Source
+    .fromURL(getClass.getResource("day7Input.txt"))
+    .mkString
+    .split('\n')
+    .toList
+    .map(_.split(" "))
+
+  val sizes = input
+    .foldLeft((List.empty[String], Map.empty[List[String], Long])) {
+      case ((path, sizes), Array("$", "cd", "/"))  => (List("/"), sizes.updated(List("/"), 0L))
+      case ((path, sizes), Array("$", "cd", "..")) => (path.dropRight(1), sizes)
+      case ((path, sizes), Array("$", "cd", cdArg)) =>
+        val fullPath = path.appended(cdArg)
+        (fullPath, sizes.updated(fullPath, 0L))
+      case ((path, sizes), Array(size, _)) if size.head.isDigit =>
+        val filteredSizes = sizes
+          .filter(key => path.startsWith(key._1))
+          .map((parentPath, totalSize) => (parentPath, totalSize + size.toLong))
+        (path, sizes.concat(filteredSizes))
+      case ((path, sizes), _) => (path, sizes)
+    }._2.values.toList.sorted
+
+  val part1 = sizes.filter(_ <= 100000).sum
+  println(s"Part 1: $part1")
+
+  val totalUsed = sizes.last
+  val part2     = sizes.find(totalUsed - _ <= 40000000).get
+
+  println(s"Part 2: $part2")
+end Day7