d2p2

d2/d2.go

@@ -40,3 +40,36 @@ func D2(input string) int64 {
 
 	return position.x * position.y
 }
+
+func D2P2(input string) int {
+	directions := strings.Split(strings.TrimSpace(input), "\n")
+	x := 0
+	y := 0
+	aim := 0
+
+	for _, direction := range directions {
+		directionAndValue := strings.Split(strings.TrimSpace(direction), " ")
+
+		if len(directionAndValue) != 2 {
+			log.Fatal("line has wrong number of elements: ", direction)
+		}
+
+		value, err := strconv.Atoi(directionAndValue[1])
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		switch directionAndValue[0] {
+		case "forward":
+			y += aim * value
+			x += value
+		case "down":
+			aim += value
+		case "up":
+			aim -= value
+		}
+	}
+
+	return x * y
+}

d2/d2_test.go

@@ -18,3 +18,16 @@ forward 2`
 
 	assert.EqualValues(t, 150, D2(input))
 }
+
+func TestD2P2(t *testing.T) {
+
+	input := `
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2`
+
+	assert.EqualValues(t, 900, D2P2(input))
+}

main.go

@@ -9,6 +9,7 @@ import (
 	"github.com/fotonmoton/aoc2021/client"
 	"github.com/fotonmoton/aoc2021/d1"
 	"github.com/fotonmoton/aoc2021/d2"
+	"github.com/fotonmoton/aoc2021/d3"
 )
 
 func main() {
@@ -24,4 +25,7 @@ func main() {
 	fmt.Printf("day 1: %v\n", d1.D1(client.Day(1)))
 	fmt.Printf("day 1 part 2: %v\n", d1.D1P2(client.Day(1)))
 	fmt.Printf("day 2: %v\n", d2.D2(client.Day(2)))
+	fmt.Printf("day 2 part 2: %v\n", d2.D2P2(client.Day(2)))
+	fmt.Printf("day 3: %v\n", d3.D3(client.Day(3)))
+
 }