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https://github.com/Luzifer/aoc2019.git
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Add solution for Day 12
Signed-off-by: Knut Ahlers <knut@ahlers.me>
This commit is contained in:
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GPG key ID:
DC2729FDD34BE99E
4 changed files with 301 additions and 0 deletions
207
day12.go
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207
day12.go
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@ -0,0 +1,207 @@
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package aoc2019
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import (
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"bufio"
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"fmt"
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"io"
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"math"
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"os"
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"regexp"
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"strconv"
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"github.com/pkg/errors"
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)
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type day12MoonSystem []*day12Moon
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func day12MoonSystemFromFile(inFile string) (day12MoonSystem, error) {
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f, err := os.Open(inFile)
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if err != nil {
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return nil, errors.Wrap(err, "Unable to open inFile")
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}
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defer f.Close()
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return day12MoonSystemFromReader(f)
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}
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func day12MoonSystemFromReader(r io.Reader) (day12MoonSystem, error) {
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var moons day12MoonSystem
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scanner := bufio.NewScanner(r)
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for scanner.Scan() {
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m, err := day12MoonFromScan(scanner.Text())
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if err != nil {
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return nil, errors.Wrap(err, "Unable to read input file")
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}
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moons = append(moons, m)
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}
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return moons, errors.Wrap(scanner.Err(), "Unable to scan file")
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}
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func (d day12MoonSystem) move(steps int) {
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for i := 0; i < steps; i++ {
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d.updateVelocity()
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for _, m := range d {
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m.move()
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}
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}
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}
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func (d day12MoonSystem) totalEnergy() int64 {
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var e int64
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for _, m := range d {
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e += m.totalEnergy()
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}
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return e
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}
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func (d day12MoonSystem) updateVelocity() {
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for _, affected := range d {
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for _, affector := range d {
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if affector == affected {
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// Moons does not affect themselves
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continue
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}
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if affector.PX > affected.PX {
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affected.VX += 1
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} else if affector.PX < affected.PX {
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affected.VX -= 1
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}
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if affector.PY > affected.PY {
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affected.VY += 1
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} else if affector.PY < affected.PY {
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affected.VY -= 1
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}
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if affector.PZ > affected.PZ {
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affected.VZ += 1
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} else if affector.PZ < affected.PZ {
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affected.VZ -= 1
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}
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}
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}
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}
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type day12Moon struct {
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PX, PY, PZ int64
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VX, VY, VZ int64
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}
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func day12MoonFromScan(scan string) (*day12Moon, error) {
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grps := regexp.MustCompile(`^<x=([0-9-]+), y=([0-9-]+), z=([0-9-]+)>$`).FindStringSubmatch(scan)
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if len(grps) != 4 {
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return nil, errors.Errorf("Invalid input %q: %#v", scan, grps)
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}
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var (
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err error
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m = &day12Moon{}
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)
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if m.PX, err = strconv.ParseInt(grps[1], 10, 64); err != nil {
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return nil, errors.Wrap(err, "Invalid X")
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}
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if m.PY, err = strconv.ParseInt(grps[2], 10, 64); err != nil {
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return nil, errors.Wrap(err, "Invalid Y")
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}
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if m.PZ, err = strconv.ParseInt(grps[3], 10, 64); err != nil {
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return nil, errors.Wrap(err, "Invalid Z")
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}
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return m, nil
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}
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func (d day12Moon) String() string {
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return fmt.Sprintf(
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"pos=<x=%d, y=%d, z=%d>, vel=<x=%d, y=%d, z=%d>",
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d.PX, d.PY, d.PZ,
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d.VX, d.VY, d.VZ,
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)
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}
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func (d *day12Moon) clearKinetic() { d.VX, d.VY, d.VZ = 0, 0, 0 }
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func (d day12Moon) eq(t *day12Moon, component int) bool {
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switch component {
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case 0:
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return d.PX == t.PX && d.VX == t.VX
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case 1:
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return d.PY == t.PY && d.VY == t.VY
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case 2:
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return d.PZ == t.PZ && d.VZ == t.VZ
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default:
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panic("Invalid component compared")
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}
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}
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func (d *day12Moon) move() {
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d.PX += d.VX
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d.PY += d.VY
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d.PZ += d.VZ
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}
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func (d day12Moon) totalEnergy() int64 {
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return int64((math.Abs(float64(d.PX)) + math.Abs(float64(d.PY)) + math.Abs(float64(d.PZ))) * (math.Abs(float64(d.VX)) + math.Abs(float64(d.VY)) + math.Abs(float64(d.VZ))))
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}
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func solveDay12Part1(inFile string) (int64, error) {
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moons, err := day12MoonSystemFromFile(inFile)
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if err != nil {
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return 0, errors.Wrap(err, "Unable to read system scan")
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}
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moons.move(1000)
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return moons.totalEnergy(), nil
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}
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func solveDay12Part2(inFile string) (int64, error) {
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moons, err := day12MoonSystemFromFile(inFile)
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if err != nil {
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return 0, errors.Wrap(err, "Unable to read system scan")
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}
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initMoons, _ := day12MoonSystemFromFile(inFile)
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var (
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iterations [3]int64
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completed [3]bool
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)
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for {
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moons.move(1)
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for c := 0; c < len(completed); c++ {
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if completed[c] {
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continue
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}
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var matches = true
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for i := range moons {
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if !moons[i].eq(initMoons[i], c) {
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matches = false
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}
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}
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iterations[c]++
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if matches {
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completed[c] = true
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}
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}
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var allComplete = true
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for _, c := range completed {
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if !c {
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allComplete = false
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}
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}
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if allComplete {
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break
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}
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}
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return leastCommonMultiple(leastCommonMultiple(iterations[0], iterations[1]), iterations[2]), nil
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}
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4
day12_input.txt
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4
day12_input.txt
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@ -0,0 +1,4 @@
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<x=-7, y=17, z=-11>
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<x=9, y=12, z=5>
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<x=-9, y=0, z=-4>
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<x=4, y=6, z=0>
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86
day12_test.go
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86
day12_test.go
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@ -0,0 +1,86 @@
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package aoc2019
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import (
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"strings"
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"testing"
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)
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func TestDay12MoonExample(t *testing.T) {
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moons, err := day12MoonSystemFromReader(strings.NewReader("<x=-1, y=0, z=2>\n<x=2, y=-10, z=-7>\n<x=4, y=-8, z=8>\n<x=3, y=5, z=-1>"))
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if err != nil {
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t.Fatalf("Unable to parse moon system: %s", err)
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}
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if l := len(moons); l != 4 {
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t.Fatalf("Unexpected moon count: exp=4 got=%d", l)
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}
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// Check initial state
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for i, expStr := range []string{
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"pos=<x=-1, y=0, z=2>, vel=<x=0, y=0, z=0>",
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"pos=<x=2, y=-10, z=-7>, vel=<x=0, y=0, z=0>",
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"pos=<x=4, y=-8, z=8>, vel=<x=0, y=0, z=0>",
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"pos=<x=3, y=5, z=-1>, vel=<x=0, y=0, z=0>",
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} {
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if s := moons[i].String(); s != expStr {
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t.Errorf("Unexpected moon %d: exp=%q got=%q", i, expStr, s)
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}
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}
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// Move moons by one step
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moons.move(1)
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// Check move state
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for i, expStr := range []string{
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"pos=<x=2, y=-1, z=1>, vel=<x=3, y=-1, z=-1>",
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"pos=<x=3, y=-7, z=-4>, vel=<x=1, y=3, z=3>",
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"pos=<x=1, y=-7, z=5>, vel=<x=-3, y=1, z=-3>",
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"pos=<x=2, y=2, z=0>, vel=<x=-1, y=-3, z=1>",
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} {
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if s := moons[i].String(); s != expStr {
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t.Errorf("Unexpected moon %d: exp=%q got=%q", i, expStr, s)
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}
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}
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// Move moons by nine more step
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moons.move(9)
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// Check move state
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for i, expStr := range []string{
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"pos=<x=2, y=1, z=-3>, vel=<x=-3, y=-2, z=1>",
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"pos=<x=1, y=-8, z=0>, vel=<x=-1, y=1, z=3>",
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"pos=<x=3, y=-6, z=1>, vel=<x=3, y=2, z=-3>",
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"pos=<x=2, y=0, z=4>, vel=<x=1, y=-1, z=-1>",
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} {
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if s := moons[i].String(); s != expStr {
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t.Errorf("Unexpected moon %d: exp=%q got=%q", i, expStr, s)
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}
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}
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// Check energy after step 10
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for i, expE := range []int64{
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36, 45, 80, 18,
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} {
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if e := moons[i].totalEnergy(); e != expE {
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t.Errorf("Unexpected energy on moon %d: exp=%d got=%d", i, expE, e)
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}
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}
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}
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func TestCalculateDay12_Part1(t *testing.T) {
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count, err := solveDay12Part1("day12_input.txt")
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if err != nil {
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t.Fatalf("Day 12 solver failed: %s", err)
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}
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t.Logf("Solution Day 12 Part 1: %d", count)
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}
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func TestCalculateDay12_Part2(t *testing.T) {
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res, err := solveDay12Part2("day12_input.txt")
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if err != nil {
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t.Fatalf("Day 12 solver failed: %s", err)
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}
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t.Logf("Solution Day 12 Part 2: %d", res)
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}
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@ -11,6 +11,10 @@ func greatestCommonDivisor(a, b int64) int64 {
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return a
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}
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func leastCommonMultiple(a, b int64) int64 {
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return a * b / greatestCommonDivisor(a, b)
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}
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func manhattenDistance(x1, y1, x2, y2 int) int {
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return int(math.Abs(float64(x1-x2)) + math.Abs(float64(y1-y2)))
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}
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