add day-19 + benchmarks

day-19/internal/one/benchmark

@@ -0,0 +1,6 @@
+goos: linux
+goarch: amd64
+pkg: github.com/onyx-and-iris/aoc2024/day-19/internal/one
+cpu: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
+BenchmarkSolve-12    	1000000000	         0.1706 ns/op
+ok  	github.com/onyx-and-iris/aoc2024/day-19/internal/one	2.018s

day-19/internal/one/solve.go

@@ -0,0 +1,58 @@
+package one
+
+import (
+	"bytes"
+	"cmp"
+	"slices"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func Solve(buf []byte) (int, error) {
+	r := bytes.NewReader(buf)
+	stripes, designs, err := parseLines(r)
+	if err != nil {
+		return 0, err
+	}
+
+	log.Debug(stripes, designs)
+
+	var sum int
+	for _, design := range designs {
+		ok := isPossibleArrangement(design, stripes)
+		if ok {
+			log.Debugf("design: %s is possible", design)
+			sum++
+		}
+	}
+
+	return sum, nil
+}
+
+func isPossibleArrangement(design string, stripes []string) bool {
+	if len(design) == 0 {
+		return true
+	}
+
+	greedy := []string{}
+	for _, stripe := range stripes {
+		log.Debugf("testing design: %s with stripe: %s", design, stripe)
+		if strings.HasPrefix(design, stripe) {
+			log.Debugf("design: %s has prefix %s", design, stripe)
+
+			greedy = append(greedy, stripe)
+		}
+	}
+
+	slices.SortFunc(greedy, func(a, b string) int {
+		return cmp.Compare(len(b), len(a))
+	})
+
+	for _, g := range greedy {
+		if isPossibleArrangement(design[len(g):], stripes) {
+			return true
+		}
+	}
+	return false
+}

day-19/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-19/internal/one/util.go

@@ -0,0 +1,33 @@
+package one
+
+import (
+	"bufio"
+	"io"
+	"strings"
+)
+
+func parseLines(r io.Reader) ([]string, []string, error) {
+	var stripes, designs []string
+
+	var inDesigns bool
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			inDesigns = true
+			continue
+		}
+
+		if inDesigns {
+			designs = append(designs, line)
+		} else {
+			stripes = strings.Split(line, ", ")
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, nil, err
+	}
+
+	return stripes, designs, nil
+}