day 12

.gitignore

@@ -2,8 +2,3 @@
 tmp
 
 # Ignore these to avoid leaking local replacements to the devkit
-./go.mod
-./go.sum
-
-go.mod
-go.sum

year25/day12/day.go

@@ -0,0 +1,149 @@
+package day12
+
+import (
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/aoc"
+	"git.bizdoc.ro/private/devkit.git/gg"
+)
+
+func Part1(ctx aoc.Context) (int, error) {
+	input, err := parseInput(ctx)
+	if err != nil {
+		return 0, fmt.Errorf("day12: failed to parse input: %w", err)
+	}
+
+	ares := make([]int, len(input.Shapes))
+	for i, shape := range input.Shapes {
+		ares[i] = shape.Area()
+	}
+
+	solution := 0
+	for _, region := range input.Regions {
+		regionSize := region.Rows * region.Cols
+		sum := 0
+		for i, count := range region.ShapeCounts {
+			sum += count * ares[i]
+		}
+		canFit := sum < regionSize
+		if canFit {
+			solution += 1
+		}
+	}
+	ctx.Println(input.String())
+	return solution, nil
+}
+
+type Shape [3][3]byte
+
+func (s *Shape) Area() int {
+	sum := 0
+	for i := range s {
+		for j := range s[i] {
+			if s[i][j] == '#' {
+				sum += 1
+			}
+		}
+	}
+	return sum
+}
+
+type Region struct {
+	Rows, Cols  int
+	ShapeCounts []int
+}
+
+func (r *Region) WriteTo(w io.Writer) (n int64, err error) {
+	out := gg.NewSafeWriter(w)
+	fmt.Fprintf(out, "%dx%d ", r.Rows, r.Cols)
+	for _, count := range r.ShapeCounts {
+		out.WriteString(strconv.Itoa(count) + " ")
+	}
+	out.WriteString("\n")
+	return out.BytesWritten(), out.Err()
+}
+
+type Input struct {
+	Shapes  []Shape
+	Regions []Region
+}
+
+func parseInput(ctx aoc.Context) (input Input, err error) {
+	text, err := ctx.BodyString()
+	if err != nil {
+		return input, fmt.Errorf("day12: failed to read input file: %w", err)
+	}
+	parts := strings.Split(text, "\n\n")
+	regionPart := parts[len(parts)-1]
+	parts = parts[0 : len(parts)-1]
+
+	input.Shapes = make([]Shape, len(parts))
+	for _, part := range parts {
+		// 0:
+		// ###
+		// ##.
+		// ##.
+		lines := strings.Split(part, "\n")
+		id, err := strconv.Atoi(lines[0][:len(lines[0])-1])
+		if err != nil {
+			return input, fmt.Errorf("day12: failed to parse shape id: %w", err)
+		}
+
+		shape := input.Shapes[id]
+		for i := range shape {
+			for j := range shape[i] {
+				shape[i][j] = lines[1+i][j]
+			}
+		}
+		input.Shapes[id] = shape // shape is value object
+	}
+
+	for _, regionStr := range strings.Split(regionPart, "\n") {
+		// 12x5: 1 0 1 0 3 2
+		var region Region
+		parts := strings.Split(regionStr, ": ")
+		for _, idstr := range strings.Split(parts[1], " ") {
+			id, err := strconv.Atoi(idstr)
+			if err != nil {
+				return input, fmt.Errorf("day12: failed to parse region id: %w", err)
+			}
+			region.ShapeCounts = append(region.ShapeCounts, id)
+		}
+
+		parts2 := strings.Split(parts[0], "x")
+		region.Rows, err = strconv.Atoi(parts2[0])
+		if err != nil {
+			return input, fmt.Errorf("day12: failed to parse region rows: %w", err)
+		}
+
+		region.Cols, err = strconv.Atoi(parts2[1])
+		if err != nil {
+			return input, fmt.Errorf("day12: failed to parse region cols: %w", err)
+		}
+		input.Regions = append(input.Regions, region)
+	}
+	return input, nil
+}
+
+func (i Input) String() string {
+	buf := strings.Builder{}
+
+	for shapeid, shape := range i.Shapes {
+		fmt.Fprintln(&buf, shapeid)
+		for i := range shape {
+			for j := range shape[i] {
+				buf.WriteString(string(shape[i][j]) + " ")
+			}
+			buf.WriteString("\n")
+		}
+		buf.WriteString("\n")
+	}
+
+	for _, region := range i.Regions {
+		region.WriteTo(&buf)
+	}
+	return buf.String()
+}

year25/day12/day_test.go

@@ -0,0 +1,18 @@
+package day12
+
+import (
+	"testing"
+
+	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/tests"
+)
+
+func TestPart1Example(t *testing.T) {
+	const want = 2
+	tests.Test(t, "example.txt", tests.Handler(Part1), want)
+}
+
+func TestPart1(t *testing.T) {
+	t.Helper()
+	const want = 510
+	tests.Test(t, "input.txt", tests.Handler(Part1), want)
+}

year25/tests/utils_test.go

@@ -1,83 +0,0 @@
-package main_test
-
-import (
-	"bytes"
-	"fmt"
-	"io"
-	"log"
-	"os"
-	"testing"
-	"time"
-
-	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/aoc"
-)
-
-func getInput(name string) io.Reader {
-	name = fmt.Sprintf("./data/%s.txt", name)
-	input, err := os.ReadFile(name)
-	if err != nil {
-		panic(err)
-	}
-	return bytes.NewReader(input)
-}
-
-func assert(t *testing.T, err error, a, b any) {
-	t.Helper()
-
-	if err != nil {
-		t.Error(err)
-	}
-	want := fmt.Sprintf("%v", a)
-	got := fmt.Sprintf("%v", b)
-	if got != want {
-		err = fmt.Errorf("want %s, got %s", want, got)
-		t.Error(err)
-	}
-}
-
-type TestCase struct {
-	Name    string
-	File    string
-	Want    any
-	Handler func(ctx aoc.Context) (any, error)
-}
-
-var StderrLogger = log.New(os.Stderr, "", 0)
-var DiscardLogger = log.New(io.Discard, "", 0)
-
-func handler[T any](f func(ctx aoc.Context) (T, error)) func(ctx aoc.Context) (any, error) {
-	return func(c aoc.Context) (any, error) {
-		return f(c)
-	}
-}
-
-func handler2[T any, K any](param T, f func(ctx aoc.Context, param T) (K, error)) func(ctx aoc.Context) (any, error) {
-	return func(c aoc.Context) (any, error) {
-		return f(c, param)
-	}
-}
-
-func runTestCase(t *testing.T, cases []TestCase, l *log.Logger) {
-
-	t.Helper()
-	var totalTime time.Duration
-	defer func() {
-		t.Log("Total time:", totalTime.String())
-	}()
-	for _, test := range cases {
-		t.Run(test.Name, func(t *testing.T) {
-			start := time.Now()
-			defer func() {
-				end := time.Since(start)
-				t.Log("elapsed:", end)
-				totalTime += end
-			}()
-			input := getInput(test.File)
-			if test.Handler == nil {
-				t.Fatalf("%s handler is nil", test.Name)
-			}
-			got, err := test.Handler(aoc.Context{Body: input, Logger: l})
-			assert(t, err, test.Want, got)
-		})
-	}
-}