Adding day 8

day8/part1.scala

@@ -0,0 +1,29 @@
+import scala.io.StdIn.readLine
+
+case class Node(c: Char, nbChild: Int, nbMetadata: Int, children: List[Node], metadata: List[Int])
+
+val it = readLine.split(" ").map(_.toInt).toList
+
+def readNode(c: Char, input: List[Int]): (Int, Node) = input match {
+  case nbChild :: nbMeta :: t =>
+    val (read, children) = List.range(0, nbChild, 1).foldLeft((0, List.empty[Node])) { case (acc, id) =>
+      val (read, node) = readNode((c + id + 1).toChar, t.drop(acc._1))
+      (acc._1 + read, node :: acc._2)
+    }
+    val metadata: List[Int] = input.drop(read + 2).take(nbMeta).toList
+  (read + 2 + nbMeta, Node(c, nbChild, nbMeta, children, metadata))
+  case _ => (0, null)
+}
+
+val rootNode = readNode('A', it)._2
+
+def sumMetadata(node: Node): Int = {
+  val childrenSum = node.children.map(sumMetadata).sum
+  val metadataSum = node.metadata.sum
+//  println(s"Node ${node.c} children sum = $childrenSum, metadataSum = $metadataSum, both = ${childrenSum + metadataSum}")
+  childrenSum + metadataSum          
+}
+
+// println(rootNode)
+
+println(sumMetadata(rootNode))

day8/part2.scala

@@ -0,0 +1,31 @@
+import scala.io.StdIn.readLine
+
+case class Node(c: Char, nbChild: Int, nbMetadata: Int, children: List[Node], metadata: List[Int]) {
+  val metaSum: Int = metadata.sum
+}
+
+val it = readLine.split(" ").map(_.toInt).toList
+
+def readNode(c: Char, input: List[Int]): (Int, Node) = input match {
+  case nbChild :: nbMeta :: t =>
+    val (read, children) = List.range(0, nbChild, 1).foldLeft((0, List.empty[Node])) { case (acc, id) =>
+      val (read, node) = readNode((c + id + 1).toChar, t.drop(acc._1))
+      (acc._1 + read, acc._2 ++ List(node))
+    }
+    val metadata: List[Int] = input.drop(read + 2).take(nbMeta).toList
+  (read + 2 + nbMeta, Node(c, nbChild, nbMeta, children, metadata))
+  case _ => (0, null)
+}
+
+val rootNode = readNode('A', it)._2
+
+def sumMetadata(node: Node): Int =
+  node match {
+    case _ if node.nbChild > 0 => node.metadata.map {
+      case m if m <= node.nbChild => sumMetadata(node.children(m - 1))
+      case _ => 0
+    }.sum
+    case _ => node.metaSum
+  }
+
+println(sumMetadata(rootNode))