Add solution for Day 11

Signed-off-by: Knut Ahlers <knut@ahlers.me>

day11.go

@@ -0,0 +1,172 @@
+package aoc2019
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/png"
+	"io/ioutil"
+	"math"
+	"os"
+	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
+)
+
+type day11PaintDirective struct {
+	X, Y  int
+	Color int64
+}
+
+func (d day11PaintDirective) positionKey() string { return fmt.Sprintf("%d:%d", d.X, d.Y) }
+
+func day11ExecutePaintRobot(inFile string, startPanelColor int64) ([]day11PaintDirective, error) {
+	var (
+		posX, posY int
+		direction  int // Clock-hand direction
+		directives = map[string]day11PaintDirective{
+			"0:0": {X: 0, Y: 0, Color: startPanelColor},
+		}
+	)
+
+	move := func() {
+		switch direction {
+		case 0:
+			posY -= 1
+		case 3:
+			posX += 1
+		case 6:
+			posY += 1
+		case 9:
+			posX -= 1
+		default:
+			panic(errors.Errorf("Invalid direction: %d", direction))
+		}
+	}
+
+	rotate := func(dir int64) {
+		var factor int
+		if dir == 1 {
+			// turn right
+			factor = 1
+		} else {
+			// turn left
+			factor = -1
+		}
+		direction = direction + factor*3
+		if direction < 0 {
+			direction += 12
+		}
+		if direction > 11 {
+			direction -= 12
+		}
+	}
+
+	// Initialize code
+	rawCode, err := ioutil.ReadFile(inFile)
+	if err != nil {
+		return nil, errors.Wrap(err, "Unable to read intcode")
+	}
+
+	code, err := parseIntcode(strings.TrimSpace(string(rawCode)))
+	if err != nil {
+		return nil, errors.Wrap(err, "Unable to parse intcode")
+	}
+
+	// Run program in background
+	var (
+		in          = make(chan int64, 1)
+		out         = make(chan int64, 2)
+		outputs     []int64
+		programExit bool
+		wg          = new(sync.WaitGroup)
+	)
+
+	go executeIntcode(code, in, out)
+	go func() {
+		for o := range out {
+			outputs = append(outputs, o)
+			wg.Done()
+		}
+		programExit = true
+	}()
+
+	// Start feeding scan results
+	for !programExit {
+		// Get previous directive for current position
+		var dir = day11PaintDirective{X: posX, Y: posY}
+		if d, ok := directives[dir.positionKey()]; ok {
+			dir = d
+		}
+
+		// Feed current color and expect two output
+		wg.Add(2)
+		in <- dir.Color
+		wg.Wait()
+
+		// Set current color
+		dir.Color = outputs[0]
+		directives[dir.positionKey()] = dir
+		// Rotate robot
+		rotate(outputs[1])
+		// Move
+		move()
+
+		// Reset outputs
+		outputs = nil
+	}
+
+	var result []day11PaintDirective
+	for _, v := range directives {
+		result = append(result, v)
+	}
+
+	return result, nil
+}
+
+func solveDay11Part1(inFile string) (int, error) {
+	dirs, err := day11ExecutePaintRobot(inFile, 0)
+	return len(dirs), errors.Wrap(err, "Unable to execute robot")
+}
+
+func solveDay11Part2(inFile string) error {
+	dirs, err := day11ExecutePaintRobot(inFile, 1)
+	if err != nil {
+		return errors.Wrap(err, "Unable to execute robot")
+	}
+
+	var minX, minY, maxX, maxY = math.MaxInt64, math.MaxInt64, 0, 0
+	for _, dir := range dirs {
+		if dir.X < minX {
+			minX = dir.X
+		}
+		if dir.X > maxX {
+			maxX = dir.X
+		}
+		if dir.Y < minY {
+			minY = dir.Y
+		}
+		if dir.Y > maxY {
+			maxY = dir.Y
+		}
+	}
+
+	colors := map[int64]color.Color{
+		0: color.RGBA{0x0, 0x0, 0x0, 0xff},
+		1: color.RGBA{0xff, 0xff, 0xff, 0xff},
+	}
+
+	img := image.NewRGBA(image.Rect(minX-5, minY-5, maxX+5, maxY+5))
+	for _, dir := range dirs {
+		img.Set(dir.X, dir.Y, colors[dir.Color])
+	}
+
+	w, err := os.Create("day11_image.png")
+	if err != nil {
+		return errors.Wrap(err, "Unable to open result image file")
+	}
+	defer w.Close()
+
+	return errors.Wrap(png.Encode(w, img), "Unable to store image")
+}

day11_input.txt

@@ -0,0 +1 @@
+3,8,1005,8,325,1106,0,11,0,0,0,104,1,104,0,3,8,102,-1,8,10,1001,10,1,10,4,10,1008,8,0,10,4,10,102,1,8,29,1006,0,41,3,8,1002,8,-1,10,101,1,10,10,4,10,1008,8,0,10,4,10,1001,8,0,54,3,8,102,-1,8,10,101,1,10,10,4,10,1008,8,1,10,4,10,102,1,8,76,1,9,11,10,2,5,2,10,2,1107,19,10,3,8,102,-1,8,10,1001,10,1,10,4,10,1008,8,0,10,4,10,101,0,8,110,2,1007,10,10,2,1103,13,10,1006,0,34,3,8,102,-1,8,10,1001,10,1,10,4,10,108,1,8,10,4,10,102,1,8,142,1006,0,32,1,101,0,10,2,9,5,10,1006,0,50,3,8,1002,8,-1,10,1001,10,1,10,4,10,1008,8,1,10,4,10,101,0,8,179,1,1005,11,10,2,1108,11,10,1006,0,10,1,1004,3,10,3,8,1002,8,-1,10,101,1,10,10,4,10,1008,8,1,10,4,10,1002,8,1,216,1,1002,12,10,2,1102,3,10,1,1007,4,10,2,101,7,10,3,8,1002,8,-1,10,1001,10,1,10,4,10,108,0,8,10,4,10,102,1,8,253,2,104,3,10,1006,0,70,3,8,102,-1,8,10,1001,10,1,10,4,10,108,1,8,10,4,10,102,1,8,282,3,8,1002,8,-1,10,101,1,10,10,4,10,1008,8,0,10,4,10,101,0,8,305,101,1,9,9,1007,9,962,10,1005,10,15,99,109,647,104,0,104,1,21102,838211572492,1,1,21102,342,1,0,1105,1,446,21102,825326674840,1,1,21101,0,353,0,1106,0,446,3,10,104,0,104,1,3,10,104,0,104,0,3,10,104,0,104,1,3,10,104,0,104,1,3,10,104,0,104,0,3,10,104,0,104,1,21101,0,29086686211,1,21102,1,400,0,1106,0,446,21102,209420786919,1,1,21101,0,411,0,1105,1,446,3,10,104,0,104,0,3,10,104,0,104,0,21101,0,838337298792,1,21101,434,0,0,1105,1,446,21101,988661154660,0,1,21102,1,445,0,1106,0,446,99,109,2,21201,-1,0,1,21101,40,0,2,21101,0,477,3,21101,0,467,0,1105,1,510,109,-2,2106,0,0,0,1,0,0,1,109,2,3,10,204,-1,1001,472,473,488,4,0,1001,472,1,472,108,4,472,10,1006,10,504,1101,0,0,472,109,-2,2106,0,0,0,109,4,1201,-1,0,509,1207,-3,0,10,1006,10,527,21102,0,1,-3,22102,1,-3,1,22102,1,-2,2,21101,0,1,3,21101,546,0,0,1105,1,551,109,-4,2105,1,0,109,5,1207,-3,1,10,1006,10,574,2207,-4,-2,10,1006,10,574,21201,-4,0,-4,1105,1,642,21201,-4,0,1,21201,-3,-1,2,21202,-2,2,3,21102,1,593,0,1105,1,551,21202,1,1,-4,21102,1,1,-1,2207,-4,-2,10,1006,10,612,21102,0,1,-1,22202,-2,-1,-2,2107,0,-3,10,1006,10,634,21202,-1,1,1,21102,1,634,0,105,1,509,21202,-2,-1,-2,22201,-4,-2,-4,109,-5,2106,0,0

day11_test.go

@@ -0,0 +1,21 @@
+package aoc2019
+
+import "testing"
+
+func TestCalculateDay11_Part1(t *testing.T) {
+	count, err := solveDay11Part1("day11_input.txt")
+	if err != nil {
+		t.Fatalf("Day 11 solver failed: %s", err)
+	}
+
+	t.Logf("Solution Day 11 Part 1: %d", count)
+}
+
+func TestCalculateDay11_Part2(t *testing.T) {
+	err := solveDay11Part2("day11_input.txt")
+	if err != nil {
+		t.Fatalf("Day 11 solver failed: %s", err)
+	}
+
+	t.Log("Solution Day 11 Part 2: See day11_image.png")
+}