2018 Day08 Complete

2018/day08/day08.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var top *Node
+
+func main() {
+	inp := StdinToString()
+	hackTheGibson(inp)
+	part1()
+	part2()
+}
+
+var nodeIndex byte
+
+func hackTheGibson(inp string) {
+	parts := strings.Split(inp, " ")
+	var rem []int
+	for i := range parts {
+		rem = append(rem, Atoi(parts[i]))
+	}
+	top, _ = parseNode(rem)
+}
+
+func parseNode(vals []int) (*Node, []int) {
+	id := nodeIndex
+	nodeIndex = nodeIndex + 1
+	retN := &Node{
+		id:         id,
+		ChildCount: vals[0],
+		MetaCount:  vals[1],
+	}
+	rem := vals[2:]
+	children := retN.ChildCount
+	if children == 0 {
+		retN.Metadata = rem[:retN.MetaCount]
+		return retN, rem[retN.MetaCount:]
+	} else {
+		var cN *Node
+		for children > 0 {
+			cN, rem = parseNode(rem)
+			retN.Children = append(retN.Children, cN)
+			children--
+		}
+		retN.Metadata = rem[:retN.MetaCount]
+		rem = rem[retN.MetaCount:]
+	}
+	return retN, rem
+}
+
+func part1() {
+	fmt.Println("= Part 1 =")
+	fmt.Println("Sum:", top.recurMetaSum())
+}
+
+func part2() {
+	fmt.Println("= Part 2 =")
+	fmt.Println(top.value())
+}
+
+type Node struct {
+	id         byte
+	ChildCount int
+	MetaCount  int
+	Metadata   []int
+	Children   []*Node
+}
+
+var indent int
+
+func (n *Node) value() int {
+	var ret int
+	if n.ChildCount == 0 {
+		for _, v := range n.Metadata {
+			ret += v
+		}
+	} else {
+		indent++
+		for _, v := range n.Metadata {
+			if v > 0 && v <= n.ChildCount {
+				ret += n.Children[v-1].value()
+			}
+		}
+		indent--
+	}
+	return ret
+}
+
+func (n *Node) recurMetaSum() int {
+	var ret int
+	for _, v := range n.Children {
+		ret += v.recurMetaSum()
+	}
+	for _, v := range n.Metadata {
+		ret += v
+	}
+	return ret
+}
+
+func (n *Node) string() string {
+	ret := fmt.Sprintf("[ %d: %d %d ]", n.id, n.ChildCount, n.MetaCount)
+	return ret
+}
+
+func StdinToString() string {
+	var input string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = input + scanner.Text()
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}