Refactor into small packages

Author: gdejong

cmd/day1/main.go

@@ -3,20 +3,20 @@ package main
 import (
 	"bufio"
 	"fmt"
-	"github.com/gdejong/advent-of-code-2024/internal"
+	"github.com/gdejong/advent-of-code-2024/internal/must"
 	"io"
 	"os"
 	"slices"
 )
 
 func main() {
-	f := internal.Must(os.Open("cmd/day1/real_input.txt"))
+	f := must.NoError(os.Open("cmd/day1/real_input.txt"))
 
 	part1answer := part1(f)
 	fmt.Println(part1answer)
 
 	// Reset the file so we can it again for part 2
-	internal.Must(f.Seek(0, io.SeekStart))
+	must.NoError(f.Seek(0, io.SeekStart))
 
 	part2answer := part2(f)
 	fmt.Println(part2answer)
@@ -33,7 +33,7 @@ func part2(f *os.File) int {
 
 		var leftNumber int
 		var rightNumber int
-		internal.Must(fmt.Sscanf(line, "%d %d", &leftNumber, &rightNumber))
+		must.NoError(fmt.Sscanf(line, "%d %d", &leftNumber, &rightNumber))
 		leftList = append(leftList, leftNumber)
 		rightList = append(rightList, rightNumber)
 	}
@@ -72,7 +72,7 @@ func part1(f *os.File) int {
 
 		var leftNumber int
 		var rightNumber int
-		internal.Must(fmt.Sscanf(line, "%d %d", &leftNumber, &rightNumber))
+		must.NoError(fmt.Sscanf(line, "%d %d", &leftNumber, &rightNumber))
 		leftList = append(leftList, leftNumber)
 		rightList = append(rightList, rightNumber)
 	}

cmd/day1/main_test.go

@@ -1,13 +1,13 @@
 package main
 
 import (
-	"github.com/gdejong/advent-of-code-2024/internal"
+	"github.com/gdejong/advent-of-code-2024/internal/must"
 	"os"
 	"testing"
 )
 
 func TestPart1(t *testing.T) {
-	f := internal.Must(os.Open("test_input.txt"))
+	f := must.NoError(os.Open("test_input.txt"))
 
 	answer := part1(f)
 
@@ -17,7 +17,7 @@ func TestPart1(t *testing.T) {
 }
 
 func TestPart2(t *testing.T) {
-	f := internal.Must(os.Open("test_input.txt"))
+	f := must.NoError(os.Open("test_input.txt"))
 
 	answer := part2(f)
 

cmd/day2/main.go

@@ -3,14 +3,16 @@ package main
 import (
 	"bufio"
 	"fmt"
-	"github.com/gdejong/advent-of-code-2024/internal"
+	"github.com/gdejong/advent-of-code-2024/internal/input"
+	"github.com/gdejong/advent-of-code-2024/internal/math"
+	"github.com/gdejong/advent-of-code-2024/internal/must"
+	"github.com/gdejong/advent-of-code-2024/internal/slices"
 	"os"
-	"strconv"
 	"strings"
 )
 
 func main() {
-	f := internal.Must(os.Open("cmd/day2/real_input.txt"))
+	f := must.NoError(os.Open("cmd/day2/real_input.txt"))
 
 	fmt.Println(part1(f))
 }
@@ -22,50 +24,34 @@ func part1(f *os.File) int {
 	for s.Scan() {
 		line := s.Text()
 
-		fields := strings.Fields(line)
-		levels := make([]int, len(fields))
+		levels := input.ToIntegers(strings.Fields(line))
 
-		// Convert to integer values
-		for k, v := range fields {
-			levels[k] = internal.Must(strconv.Atoi(v))
-		}
-
-		// Calculate the differences
-		diffs := make([]int, len(levels)-1)
-		for index := range len(levels) - 1 {
-			diffs[index] = levels[index+1] - levels[index]
-		}
-
-		allIncreasing := func(val int) bool { return val > 0 }
-		allDecreasing := func(val int) bool { return val < 0 }
-		allBetweenOneAndThree := func(val int) bool { return Abs(val) >= 1 && Abs(val) <= 3 }
-
-		isAllIncreasing := All(diffs, allIncreasing)
-		isAllDecreasing := All(diffs, allDecreasing)
-		IsAllDifferByAtLeastOneAndAtMostThree := All(diffs, allBetweenOneAndThree)
-
-		if (isAllIncreasing || isAllDecreasing) && IsAllDifferByAtLeastOneAndAtMostThree {
+		if isSafeReport(levels) {
 			safeCounter++
 		}
-
 	}
 
 	return safeCounter
 }
 
-func Abs(value int) int {
-	if value < 0 {
-		value = value * -1
+func isSafeReport(levels []int) bool {
+	// Calculate the differences
+	diffs := make([]int, len(levels)-1)
+	for index := range len(levels) - 1 {
+		diffs[index] = levels[index+1] - levels[index]
 	}
 
-	return value
-}
+	allIncreasing := func(val int) bool { return val > 0 }
+	allDecreasing := func(val int) bool { return val < 0 }
+	allBetweenOneAndThree := func(val int) bool { return math.Abs(val) >= 1 && math.Abs(val) <= 3 }
 
-func All[T any](ts []T, pred func(T) bool) bool {
-	for _, t := range ts {
-		if !pred(t) {
-			return false
-		}
+	isAllIncreasing := slices.All(diffs, allIncreasing)
+	isAllDecreasing := slices.All(diffs, allDecreasing)
+	IsAllDifferByAtLeastOneAndAtMostThree := slices.All(diffs, allBetweenOneAndThree)
+
+	if (isAllIncreasing || isAllDecreasing) && IsAllDifferByAtLeastOneAndAtMostThree {
+		return true
 	}
-	return true
+
+	return false
 }

cmd/day2/main_test.go

@@ -1,13 +1,13 @@
 package main
 
 import (
-	"github.com/gdejong/advent-of-code-2024/internal"
+	"github.com/gdejong/advent-of-code-2024/internal/must"
 	"os"
 	"testing"
 )
 
 func TestPart1(t *testing.T) {
-	f := internal.Must(os.Open("test_input.txt"))
+	f := must.NoError(os.Open("test_input.txt"))
 
 	answer := part1(f)
 

internal/input/input.go

@@ -0,0 +1,17 @@
+package input
+
+import (
+	"github.com/gdejong/advent-of-code-2024/internal/must"
+	"strconv"
+)
+
+func ToIntegers(input []string) []int {
+	integers := make([]int, len(input))
+
+	// Convert to integer values
+	for k, v := range input {
+		integers[k] = must.NoError(strconv.Atoi(v))
+	}
+
+	return integers
+}

internal/math/math.go

@@ -0,0 +1,9 @@
+package math
+
+func Abs(value int) int {
+	if value < 0 {
+		value = value * -1
+	}
+
+	return value
+}

internal/must.go

@@ -0,0 +1,10 @@
+package must
+
+// NoError takes in some value and an error, and panics if the error is not nil.
+func NoError[t any](something t, err error) t {
+	if err != nil {
+		panic(err)
+	}
+
+	return something
+}

internal/must/must.go

@@ -0,0 +1,11 @@
+package slices
+
+// All accepts a slice and a predicate function. It will return true if the predicate is true for all slice elements.
+func All[T any](ts []T, pred func(T) bool) bool {
+	for _, t := range ts {
+		if !pred(t) {
+			return false
+		}
+	}
+	return true
+}