add day-10 + benchmarks

day-10/internal/one/benchmark

@@ -0,0 +1,6 @@
+goos: linux
+goarch: amd64
+pkg: github.com/onyx-and-iris/aoc2024/day-10/internal/one
+cpu: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
+BenchmarkSolve-12    	1000000000	         0.001398 ns/op
+ok  	github.com/onyx-and-iris/aoc2024/day-10/internal/one	0.014s

day-10/internal/one/direction.go

@@ -0,0 +1,9 @@
+package one
+
+const (
+	N = iota
+	E
+	S
+	W
+	None
+)

day-10/internal/one/graph.go

@@ -0,0 +1,40 @@
+package one
+
+import (
+	"slices"
+	"strings"
+)
+
+type point struct {
+	x int
+	y int
+}
+
+type graph struct {
+	data           []string
+	startPositions []point
+}
+
+func newGrid() *graph {
+	return &graph{data: make([]string, 0), startPositions: make([]point, 0)}
+}
+
+func (g *graph) String() string {
+	return strings.Join(g.data, "\n")
+}
+
+func (g *graph) isOutOfBounds(p point) bool {
+	return p.x < 0 || p.y < 0 || p.y >= len(g.data) || p.x >= len(g.data[p.y])
+}
+
+func (g *graph) valueAt(p point) rune {
+	return rune(g.data[p.y][p.x])
+}
+
+func (g *graph) debug(path []point) string {
+	temp := slices.Clone(g.data)
+	for _, pos := range path {
+		temp[pos.y] = replaceAtIndex(temp[pos.y], '+', pos.x)
+	}
+	return strings.Join(temp, "\n")
+}

day-10/internal/one/neighbours.go

@@ -0,0 +1,10 @@
+package one
+
+func neighbours(p point) [4]point {
+	return [4]point{
+		{p.x, p.y - 1},
+		{p.x + 1, p.y},
+		{p.x, p.y + 1},
+		{p.x - 1, p.y},
+	}
+}

day-10/internal/one/solve.go

@@ -0,0 +1,68 @@
+package one
+
+import (
+	"bytes"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/onyx-and-iris/aoc2024/day-10/internal/queue"
+)
+
+const target = '9'
+
+func Solve(buf []byte) (int, error) {
+	r := bytes.NewReader(buf)
+	graph, err := parseLines(r)
+	if err != nil {
+		return 0, err
+	}
+
+	var totalScore int
+	queue := queue.New[point]()
+	for _, pos := range graph.startPositions {
+		if graph.isOutOfBounds(pos) {
+			continue
+		}
+		queue.Enqueue(pos)
+
+		var score int
+		visited := make(map[point]struct{})
+		endpoints := make(map[point]struct{})
+		for !queue.IsEmpty() {
+			current := queue.Dequeue()
+
+			_, ok := endpoints[current]
+			if ok {
+				continue
+			}
+			endpoints[current] = struct{}{}
+
+			if graph.valueAt(current) == target {
+				score++
+				continue
+			}
+
+			_, ok = visited[current]
+			if ok {
+				continue
+			}
+			visited[current] = struct{}{}
+
+			for _, n := range neighbours(current) {
+				if graph.isOutOfBounds(n) {
+					continue
+				}
+
+				if graph.valueAt(n)-graph.valueAt(current) == 1 {
+					log.Tracef("pushing %v with value %s back onto the queue\n", n, string(graph.valueAt(n)))
+					queue.Enqueue(n)
+				}
+			}
+		}
+
+		log.Debugf("score for trailhead %v - %d\n", pos, score)
+		totalScore += score
+	}
+
+	return totalScore, nil
+}

day-10/internal/one/solve_internal_test.go

@@ -0,0 +1,15 @@
+package one
+
+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-10/internal/one/util.go

@@ -0,0 +1,45 @@
+package one
+
+import (
+	"bufio"
+	"io"
+	"regexp"
+
+	log "github.com/sirupsen/logrus"
+)
+
+var reStartPos = regexp.MustCompile(`0`)
+
+func parseLines(r io.Reader) (*graph, error) {
+	graph := newGrid()
+
+	var linecount int
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		graph.data = append(graph.data, line)
+		for _, m := range reStartPos.FindAllStringIndex(line, -1) {
+			graph.startPositions = append(
+				graph.startPositions,
+				point{x: m[0], y: linecount},
+			)
+		}
+
+		linecount++
+	}
+
+	log.Debug(graph.startPositions)
+
+	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)
+}