Day 17: Part 1

Signed-off-by: James Griffin <james@unsupervised.ca>

main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"fmt"
 
-	"github.com/thatguygriff/aoc2020/sixteen"
+	"github.com/thatguygriff/aoc2020/seventeen"
 )
 
 func main() {
@@ -68,6 +68,9 @@ func main() {
 	// fmt.Println(fifteen.PartTwo())
 
 	// Day 16
-	fmt.Println(sixteen.PartOne())
-	fmt.Println(sixteen.PartTwo())
+	// fmt.Println(sixteen.PartOne())
+	// fmt.Println(sixteen.PartTwo())
+
+	// Day 17
+	fmt.Println(seventeen.PartOne())
 }

seventeen/day_seventeen.go

@@ -0,0 +1,148 @@
+package seventeen
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+type pocket struct {
+	dimension [][][]bool
+}
+
+func (p *pocket) initialize(filename string) error {
+	file, err := os.Open(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	y := 0
+	z := 0
+	p.dimension = [][][]bool{}
+	p.dimension = append(p.dimension, [][]bool{})
+	for scanner.Scan() {
+		p.dimension[z] = append(p.dimension[z], []bool{})
+		for _, c := range scanner.Text() {
+			switch string(c) {
+			case "#":
+				p.dimension[z][y] = append(p.dimension[z][y], true)
+			case ".":
+				p.dimension[z][y] = append(p.dimension[z][y], false)
+			}
+		}
+		y++
+	}
+
+	return nil
+}
+
+func (p *pocket) active() int {
+	count := 0
+
+	for z := 0; z < len(p.dimension); z++ {
+		for y := 0; y < len(p.dimension[z]); y++ {
+			for x := 0; x < len(p.dimension[z][y]); x++ {
+				if p.dimension[z][y][x] {
+					count++
+				}
+			}
+		}
+	}
+
+	return count
+}
+
+func activation(p pocket, x, y, z int) bool {
+	activeNeighbours := 0
+	selfActive := false
+	for zIndex := z - 1; zIndex <= z+1; zIndex++ {
+		if zIndex < 0 || zIndex >= len(p.dimension) {
+			continue
+		}
+		for yIndex := y - 1; yIndex <= y+1; yIndex++ {
+			if yIndex < 0 || yIndex >= len(p.dimension[zIndex]) {
+				continue
+			}
+			for xIndex := x - 1; xIndex <= x+1; xIndex++ {
+				if xIndex < 0 || xIndex >= len(p.dimension[zIndex][yIndex]) {
+					continue
+				}
+
+				if xIndex == x && yIndex == y && zIndex == z {
+					selfActive = p.dimension[zIndex][yIndex][xIndex]
+					continue
+				}
+
+				if p.dimension[zIndex][yIndex][xIndex] {
+					activeNeighbours++
+				}
+			}
+		}
+	}
+
+	if selfActive {
+		if activeNeighbours == 2 || activeNeighbours == 3 {
+			return true
+		}
+	} else {
+		if activeNeighbours == 3 {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (p *pocket) print() {
+	for z := 0; z < len(p.dimension); z++ {
+		fmt.Printf("\nz=%d\n", z)
+		for y := 0; y < len(p.dimension[z]); y++ {
+			yString := ""
+			for x := 0; x < len(p.dimension[z][y]); x++ {
+				if p.dimension[z][y][x] {
+					yString += "#"
+				} else {
+					yString += "."
+				}
+			}
+			fmt.Println(yString)
+		}
+	}
+}
+
+func simulate(start pocket, count int) pocket {
+	simulated := start
+
+	for round := 0; round < count; round++ {
+		next := pocket{
+			dimension: make([][][]bool, len(simulated.dimension)+2),
+		}
+
+		for z := -1; z < len(simulated.dimension)+1; z++ {
+			next.dimension[z+1] = make([][]bool, len(simulated.dimension[0])+2)
+			for y := -1; y < len(simulated.dimension[0])+1; y++ {
+				next.dimension[z+1][y+1] = make([]bool, len(simulated.dimension[0][0])+2)
+				for x := -1; x < len(simulated.dimension[0][0])+1; x++ {
+					next.dimension[z+1][y+1][x+1] = activation(simulated, x, y, z)
+				}
+			}
+		}
+
+		simulated = next
+	}
+
+	return simulated
+}
+
+// PartOne How many active cubes are left after 6 cycles
+func PartOne() string {
+	p := pocket{}
+	if err := p.initialize("seventeen/input.txt"); err != nil {
+		return err.Error()
+	}
+
+	p = simulate(p, 6)
+	return fmt.Sprintf("There are %d active cubes after 6 rounds", p.active())
+}

seventeen/day_seventeen_test.go

@@ -0,0 +1,51 @@
+package seventeen
+
+import "testing"
+
+func Test_dimension_init(t *testing.T) {
+	p := pocket{}
+	if err := p.initialize("sample.txt"); err != nil {
+		t.Logf(err.Error())
+		t.FailNow()
+	}
+
+	active := p.active()
+	if active != 5 {
+		t.Logf("Expected 5 active after 0 rounds, found %d", active)
+		t.FailNow()
+	}
+}
+
+func Test_dimension_simulate1(t *testing.T) {
+	p := pocket{}
+	if err := p.initialize("sample.txt"); err != nil {
+		t.Logf(err.Error())
+		t.FailNow()
+	}
+	p.print()
+
+	p = simulate(p, 1)
+	p.print()
+
+	active := p.active()
+	if active != 12 {
+		t.Logf("Expected 11 active after 1 rounds, found %d", active)
+		t.FailNow()
+	}
+}
+
+func Test_dimension_simulate(t *testing.T) {
+	p := pocket{}
+	if err := p.initialize("sample.txt"); err != nil {
+		t.Logf(err.Error())
+		t.FailNow()
+	}
+
+	p = simulate(p, 6)
+	p.print()
+	active := p.active()
+	if active != 112 {
+		t.Logf("Expected 112 active after 6 rounds, found %d", active)
+		t.FailNow()
+	}
+}

seventeen/input.txt

@@ -0,0 +1,8 @@
+###...#.
+.##.####
+.####.##
+###.###.
+.##.####
+#.##..#.
+##.####.
+.####.#.

seventeen/sample.txt

@@ -0,0 +1,3 @@
+.#.
+..#
+###