Day9

day8/day8.go

@@ -3,6 +3,7 @@ package main
 import (
 	"AOC2022/helper"
 	"fmt"
+	"os"
 )
 
 type Tree struct {
@@ -11,8 +12,8 @@ type Tree struct {
 }
 
 func main() {
-	//args := os.Args[1:]
-	lines := helper.ReadTextFile("day8/input")
+	args := os.Args[1:]
+	lines := helper.ReadTextFile(args[0])
 	forest := make([][]Tree, len(lines))
 	for i, line := range lines {
 		forest[i] = make([]Tree, len(line))

day9/day9.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"AOC2022/helper"
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Simulation struct {
+	headPos  [2]int
+	tailPos  [][2]int
+	tailPast map[[2]int]bool
+}
+
+func main() {
+	args := os.Args[1:]
+	lines := helper.ReadTextFile(args[0])
+	tails := [][2]int{{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}}
+	simulation := Simulation{[2]int{0, 0}, tails, make(map[[2]int]bool)}
+	for _, line := range lines {
+		direction, distance := getDirectionAndDistance(line)
+		for i := 0; i < distance; i++ {
+			move(&simulation.headPos, direction)
+			for i, _ := range tails {
+				simulation.moveTail(i)
+			}
+		}
+	}
+
+	fmt.Println(len(simulation.tailPast))
+}
+
+func getDirectionAndDistance(line string) ([2]int, int) {
+	splitLine := strings.Split(line, " ")
+	distance := helper.RemoveError(strconv.Atoi(splitLine[1]))
+	switch splitLine[0] {
+	case "U":
+		return [2]int{0, 1}, distance
+	case "D":
+		return [2]int{0, -1}, distance
+	case "R":
+		return [2]int{1, 0}, distance
+	case "L":
+		return [2]int{-1, 0}, distance
+	default:
+		return [2]int{0, 0}, distance
+	}
+}
+
+func (simulation *Simulation) moveTail(i int) {
+	activeTail := &simulation.tailPos[i]
+	if len(simulation.tailPos)-1 == i {
+		simulation.tailPast[*activeTail] = true
+	}
+	var nextKnot [2]int
+	if i == 0 {
+		nextKnot = simulation.headPos
+	} else {
+		nextKnot = simulation.tailPos[i-1]
+	}
+	direction := getDirectionFromTo(nextKnot[:], activeTail[:])
+	if getLength(direction[:]) < 2 {
+		return
+	}
+	if direction[0] > 0 {
+		activeTail[0]++
+	}
+	if direction[0] < 0 {
+		activeTail[0]--
+	}
+	if direction[1] > 0 {
+		activeTail[1]++
+	}
+	if direction[1] < 0 {
+		activeTail[1]--
+	}
+	if len(simulation.tailPos)-1 == i {
+		simulation.tailPast[*activeTail] = true
+	}
+}
+
+func move(object *[2]int, direction [2]int) {
+	object[0] += direction[0]
+	object[1] += direction[1]
+}
+
+func getDirectionFromTo(X, Y []int) []int {
+	direction := []int{}
+	for i, _ := range X {
+		direction = append(direction, X[i]-Y[i])
+	}
+	return direction
+}
+
+func getLength(X []int) float64 {
+	temp := float64(0)
+	for i, _ := range X {
+		temp += math.Pow(float64(X[i]), 2)
+	}
+	return math.Sqrt(temp)
+}
+
+func (simulation *Simulation) print(size int) {
+	for i := 0; i < size; i++ {
+		tempArr := ""
+		for j := 0; j < size; j++ {
+			pos := [2]int{j, size - 1 - i}
+			if [2]int{0, 0} == pos {
+				tempArr += "S"
+			} else if simulation.tailPast[pos] {
+				tempArr += "#"
+			} else if simulation.headPos == pos {
+				tempArr += "H"
+			} else if helper.Contains(simulation.tailPos, pos) {
+				tempArr += "T"
+			} else {
+				tempArr += "."
+			}
+		}
+		fmt.Println(tempArr)
+	}
+}

day9/testinput

@@ -0,0 +1,8 @@
+R 4
+U 4
+L 3
+D 1
+R 4
+D 1
+L 5
+R 2

day9/testinput2

@@ -0,0 +1,8 @@
+R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20

helper/helper.go

@@ -77,3 +77,12 @@ func Sum[T int | int64](slice []T) (s T) {
 	}
 	return
 }
+
+func Contains[T [2]int](elems []T, v T) bool {
+	for _, s := range elems {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}