add day-20

day-20/internal/two/graph.go

@@ -0,0 +1,38 @@
+package two
+
+import (
+	"slices"
+	"strings"
+
+	"github.com/onyx-and-iris/aoc2024/day-20/internal/point"
+
+	"github.com/elliotchance/orderedmap/v3"
+)
+
+type graph struct {
+	start, end point.Point
+	data       []string
+}
+
+func newGraph(data []string) *graph {
+	return &graph{data: data}
+}
+
+func (g *graph) String() string {
+	return strings.Join(g.data, "\n")
+}
+
+func (g *graph) valueAt(p point.Point) rune {
+	return rune(g.data[p.Y][p.X])
+}
+
+func (g *graph) debug(path *orderedmap.OrderedMap[point.Point, int]) string {
+	temp := slices.Clone(g.data)
+	for n := range path.Keys() {
+		if g.valueAt(n) == 'X' {
+			continue
+		}
+		temp[n.Y] = replaceAtIndex(temp[n.Y], 'O', n.X)
+	}
+	return strings.Join(temp, "\n")
+}

day-20/internal/two/solve.go

@@ -0,0 +1,38 @@
+package two
+
+import (
+	"bytes"
+	"math"
+
+	"github.com/onyx-and-iris/aoc2024/day-20/internal/one"
+	"github.com/onyx-and-iris/aoc2024/day-20/internal/point"
+	log "github.com/sirupsen/logrus"
+)
+
+func Solve(buf []byte) (int, error) {
+	r := bytes.NewReader(buf)
+	graph, err := parseLines(r)
+	if err != nil {
+		return 0, err
+	}
+
+	log.Debugf("\n%s\n", graph.debug(one.Path))
+
+	var count int
+	for pair1 := one.Path.Front(); pair1 != nil; pair1 = pair1.Next() {
+		for pair2 := one.Path.Front(); pair2 != nil; pair2 = pair2.Next() {
+			if manhatten(pair1.Key, pair2.Key) > 20 ||
+				pair1.Value-pair2.Value-manhatten(pair1.Key, pair2.Key) < 100 {
+				continue
+			}
+
+			count++
+		}
+	}
+
+	return count, nil
+}
+
+func manhatten(a, b point.Point) int {
+	return int(math.Abs(float64(a.X)-float64(b.X)) + math.Abs(float64(a.Y)-float64(b.Y)))
+}

day-20/internal/two/solve_internal_test.go

@@ -0,0 +1,15 @@
+package two
+
+import (
+	_ "embed"
+	"os"
+	"testing"
+)
+
+//go:embed testdata/input.txt
+var data []byte
+
+func BenchmarkSolve(b *testing.B) {
+	os.Stdout, _ = os.Open(os.DevNull)
+	Solve(data)
+}

day-20/internal/two/util.go

@@ -0,0 +1,44 @@
+package two
+
+import (
+	"bufio"
+	"io"
+	"strings"
+
+	"github.com/onyx-and-iris/aoc2024/day-20/internal/point"
+)
+
+func parseLines(r io.Reader) (*graph, error) {
+	graph := newGraph(make([]string, 0))
+
+	var linecount int
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if strings.Contains(line, "S") {
+			indx := strings.Index(line, "S")
+			graph.start = point.New(indx, linecount)
+		}
+		if strings.Contains(line, "E") {
+			indx := strings.Index(line, "E")
+			graph.end = point.New(indx, linecount)
+		}
+
+		graph.data = append(graph.data, line)
+
+		linecount++
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return graph, nil
+}
+
+func replaceAtIndex(s string, r rune, i int) string {
+	out := []rune(s)
+	out[i] = r
+	return string(out)
+}