Day 8.2 solution.

2018/internal/day08/tree.go

@@ -5,6 +5,14 @@ type Node struct {
 	Metadata []int
 }
 
+func (node Node) SumMetadata() int {
+	sum := 0
+	for _, v := range node.Metadata {
+		sum += v
+	}
+	return sum
+}
+
 func BuildTree(data []int) *Node {
 	root, _ := buildTreeR(data, 0)
 	return root