2019 Day 6 Complete!

2019-12-06 08:00:17 -06:00
parent d5fb449c31
commit 930491c840
4 changed files with 1171 additions and 0 deletions
--- a/2019/day06/main.go
+++ b/2019/day06/main.go
@@ -0,0 +1,162 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	helpers "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := helpers.StdinToStringSlice()
+	allObjects = make(map[string]*Object)
+	for _, v := range inp {
+		pts := strings.Split(v, ")")
+		var obj1, obj2 *Object
+		var ok bool
+		if obj1, ok = allObjects[pts[0]]; !ok {
+			obj1 = NewObject(pts[0])
+			allObjects[pts[0]] = obj1
+		}
+		if obj2, ok = allObjects[pts[1]]; !ok {
+			obj2 = NewObject(pts[1])
+			allObjects[pts[1]] = obj2
+			obj1.addMoon(pts[1])
+		}
+		obj2.setOrbiting(pts[0])
+	}
+	fmt.Println(len(allObjects), "total objects")
+	part1()
+	part2()
+}
+
+func part1() {
+	var ret int
+	for _, v := range allObjects {
+		ret += v.countOrbits()
+	}
+	fmt.Println("Part 1:", ret)
+}
+
+func part2() {
+	if _, ok := allObjects["YOU"]; !ok {
+		panic("Invalid input for part 2")
+	}
+	if _, ok := allObjects["SAN"]; !ok {
+		panic("Invalid input for part 2")
+	}
+	you := allObjects["YOU"]
+	youOrbits := you.getOrbitsList()
+	san := allObjects["SAN"]
+	sanOrbits := san.getOrbitsList()
+	min := -1
+	var minShared *Object
+	for _, yv := range youOrbits {
+		for _, sv := range sanOrbits {
+			if yv == sv {
+				ySteps := you.stepsTo(yv.Name)
+				sSteps := san.stepsTo(sv.Name)
+				if min == -1 || ySteps+sSteps < min {
+					min = ySteps + sSteps
+					minShared = yv
+				}
+			}
+		}
+	}
+	if minShared == nil {
+		panic("No shared object found!")
+	}
+	fmt.Println("Closest Ancestor: ", minShared.Name)
+	fmt.Println("Steps: ", min)
+}
+
+var allObjects map[string]*Object
+
+type Object struct {
+	Name   string
+	Moons  []*Object
+	Orbits *Object
+}
+
+func NewObject(nm string) *Object {
+	return &Object{Name: nm}
+}
+
+func (o *Object) getOrbitsList() []*Object {
+	var ret []*Object
+	if o.Orbits == nil {
+		return ret
+	}
+	ret = append(ret, o.Orbits)
+	return append(ret, o.Orbits.getOrbitsList()...)
+}
+
+func (o *Object) stepsTo(nm string) int {
+	// First check if this is it
+	if o.Name == nm {
+		// If so, remove the last transfer
+		return -1
+	}
+	// Now check if it's a descendant of this
+	if ret := o.hasDesc(nm); ret != nil {
+		return ret.stepsTo(nm) + 1
+	}
+	// Ok, we must have to go up another level
+	if o.Orbits == nil {
+		fmt.Println(o.Name)
+		panic("Nothing else to check!")
+	}
+	return o.Orbits.stepsTo(nm) + 1
+}
+
+func (o *Object) OrbitsAround(nm string) bool {
+	if o.Orbits == nil {
+		return false
+	}
+	if o.Orbits.Name == nm {
+		return true
+	}
+	return o.Orbits.OrbitsAround(nm)
+}
+
+// hasDesc checks all moons to see if one is or has the requested moon
+// and returns the object that does
+func (o *Object) hasDesc(nm string) *Object {
+	for _, v := range o.Moons {
+		if v.Name == nm {
+			return v
+		}
+		if d := v.hasDesc(nm); d != nil {
+			return d
+		}
+	}
+	return nil
+}
+
+func (o *Object) countOrbits() int {
+	if o.Name == "COM" {
+		return 0
+	}
+	return o.Orbits.countOrbits() + 1
+}
+
+func (o *Object) setOrbiting(nm string) {
+	if v, ok := allObjects[nm]; !ok {
+		panic(fmt.Sprintf("Object not found (%s)", nm))
+	} else {
+		o.Orbits = v
+	}
+}
+
+func (o *Object) addMoon(nm string) {
+	if v, ok := allObjects[nm]; !ok {
+		panic(fmt.Sprintf("Object not found (%s)", nm))
+	} else {
+		for k := range o.Moons {
+			if o.Moons[k].Name == nm {
+				return
+			}
+		}
+		o.Moons = append(o.Moons, v)
+	}
+}