Day 08

Signed-off-by: Ettore <noettore@gmail.com>

2018/day_08/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type node struct {
+	children []*node
+	metadata []int
+}
+
+func treeRecursiveBuild(info *[]int) (*node, int) {
+	n := &node{}
+	metaSum := 0
+	childNum := (*info)[0]
+	metaNum := (*info)[1]
+
+	*info = (*info)[2:]
+
+	for i := 0; i < childNum; i++ {
+		children, s := treeRecursiveBuild(info)
+		metaSum += s
+		n.children = append(n.children, children)
+	}
+
+	for i := 0; i < metaNum; i++ {
+		metaSum += (*info)[0]
+		n.metadata = append(n.metadata, (*info)[0])
+		if len(*info) > 0 {
+			*info = (*info)[1:]
+		}
+	}
+
+	return n, metaSum
+}
+
+func (n *node) value() int {
+	value := 0
+	if len(n.children) == 0 {
+		for _, m := range n.metadata {
+			value += m
+		}
+	} else {
+		for _, m := range n.metadata {
+			if m <= len(n.children) {
+				value += n.children[m-1].value()
+			}
+		}
+	}
+	return value
+}
+
+func main() {
+	var info []int
+	file, err := os.Open("./input")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	scan := bufio.NewScanner(file)
+	scan.Scan()
+	line := scan.Text()
+
+	for _, n := range strings.Split(line, " ") {
+		num, _ := strconv.Atoi(n)
+		info = append(info, num)
+	}
+
+	root, metaSum := treeRecursiveBuild(&info)
+
+	fmt.Printf("Part One: %v\n", metaSum)
+
+	fmt.Printf("Part Two: %v\n", root.value())
+
+}