add day-13 + benchmarks

day-13/internal/two/benchmark

@@ -0,0 +1,6 @@
+goos: linux
+goarch: amd64
+pkg: github.com/onyx-and-iris/aoc2024/day-13/internal/two
+cpu: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
+BenchmarkSolve-12    	1000000000	         0.0006422 ns/op
+ok  	github.com/onyx-and-iris/aoc2024/day-13/internal/two	0.010s

day-13/internal/two/solve.go

@@ -0,0 +1,45 @@
+package two
+
+import (
+	"bytes"
+	"math"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/onyx-and-iris/aoc2024/day-13/internal/util"
+)
+
+const augment = 10e12
+
+func Solve(buf []byte) (int, error) {
+	r := bytes.NewReader(buf)
+	machines, err := util.ParseLines(r)
+	if err != nil {
+		return 0, err
+	}
+
+	var total int
+	for _, m := range machines {
+		m.Prize.X += augment
+		m.Prize.Y += augment
+
+		denominator := ((m.A.X * m.B.Y) - (m.B.X * m.A.Y))
+		a_numerator := ((m.Prize.X * m.B.Y) - (m.Prize.Y * m.B.X))
+		b_numerator := ((m.Prize.Y * m.A.X) - (m.Prize.X * m.A.Y))
+
+		a := float64(a_numerator) / float64(denominator)
+		b := float64(b_numerator) / float64(denominator)
+
+		if a != math.Round(a) || b != math.Round(b) {
+			continue
+		}
+
+		log.Debug(a, b)
+
+		if a > 0 && b > 0 {
+			total += 3*int(a) + int(b)
+		}
+	}
+
+	return total, nil
+}

day-13/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)
+}