day2

2024/go/day02/day02.go

@@ -0,0 +1,105 @@
+package day02
+
+import (
+	"adventofcode2024/utils"
+	_ "adventofcode2024/utils"
+	_ "adventofcode2024/utils/grid2d"
+	_ "adventofcode2024/utils/inputs"
+	_ "errors"
+	_ "fmt"
+	"strings"
+)
+
+type Dir int
+
+const (
+    Up Dir = iota
+    Down
+    Safe
+	Unsafe
+)
+
+// Implement the Stringer interface
+func (d Dir) String() string {
+    switch d {
+    case Up:
+        return "Up"
+    case Down:
+        return "Down"
+    case Safe:
+        return "Safe"
+	case Unsafe:
+        return "Unsafe"
+	default:
+		return "Unknown"
+    }
+}
+
+func Part1(input string) int {
+	count := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		if isSafe(fields) {count++}
+	}
+	return count
+}
+
+func Part2(input string) int {
+	count := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		if isSafe(fields) {
+			count++
+		} else {
+			for i := 0; i < len(fields); i++ {
+				// Create a new slice excluding the current item
+				newFields := applyDampner(fields, i)
+				if isSafe(newFields) {
+					count++
+					break
+				}
+			}
+		}
+	}
+	return count
+}
+
+func isSafe(fields []string) bool {
+	Dir := getDir(utils.MustAtoi(fields[0]), utils.MustAtoi(fields[1]))
+	if Dir == Unsafe {
+			return false
+	}
+	for x := 2; x < len(fields); x++ {
+		NextDir := getDir(utils.MustAtoi(fields[x-1]), utils.MustAtoi(fields[x]))
+		if NextDir == Unsafe {
+			return false
+		}
+		if NextDir != Dir {
+			return false
+		}
+	}
+	return true
+}
+
+func getDir(a int, b int) Dir {
+	var dir Dir
+	diff := b - a
+	if diff > 0 && utils.Abs(diff) < 4 {
+		dir = Up
+	} else if diff < 0 && utils.Abs(diff) < 4 {
+		dir = Down
+	} else {
+		dir = Unsafe
+	}
+	return dir
+}
+
+func applyDampner(fields []string, pos int) []string {
+	copy := append([]string{}, fields...)
+    if pos < 0 || pos >= len(copy) {
+        return copy // Return the fields unchanged if pos is invalid
+    }
+    return append(copy[:pos], copy[pos+1:]...)
+}

2024/go/day02/day02_test.go

@@ -0,0 +1,29 @@
+package day02
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(		
+`7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9`)
+	require.Equal(t, 2, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(
+`7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9`)
+	require.Equal(t, 4, r)
+}

2024/go/main.go

@@ -8,6 +8,7 @@ import (
 //	"time"
 	"adventofcode2024/utils"
 	"adventofcode2024/day01"
+	"adventofcode2024/day02"
 )
 // Usage: go run main.go <NN>
 // assumes input is in day<NN>/input.txt
@@ -19,6 +20,9 @@ func main() {
 	case 1:
 		fmt.Printf("part 1: %d\n", day01.Part1(utils.Readfile(d)))
 		fmt.Printf("part 2: %d\n", day01.Part2(utils.Readfile(d)))
+	case 2:
+		fmt.Printf("part 1: %d\n", day02.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day02.Part2(utils.Readfile(d)))
 	default:
 		panic(fmt.Errorf("no such day: %d", d))
 	}

2024/go/utils/inputs/inputs.go

@@ -21,7 +21,7 @@ func ToInts(input string, sep string) []int {
 func ToGrid2D[T any](input, rowSep, colSep string, empty T, conv func(string) T) *grid2d.Grid[T] {
 	lines := strings.Split(input, rowSep)
 
-	grid := grid2d.NewGrid(len(lines[0]), len(lines), empty)
+	grid := grid2d.NewGrid(len(lines[0]) - strings.Count(lines[0], colSep), len(lines), empty)
 	for y, line := range lines {
 		for x, v := range strings.Split(line, colSep) {
 			grid.Set(x, y, conv(v))