Solve 2024 day 1 part B

src/2024/day01/go/main.go

@@ -44,15 +44,59 @@ func calculateDistances(input *os.File) (int, error) {
 	return sum, nil
 }
 
+func similarityScore(input *os.File) (int, error) {
+	scanner := bufio.NewScanner(input)
+	sum := 0
+	a := make([]int, 0)
+	b := make([]int, 0)
+	for scanner.Scan() {
+		line := scanner.Text()
+		first := strings.Split(line, "   ")[0]
+		firstN, err := strconv.Atoi(first)
+		if err != nil {
+			log.Fatal(err)
+		}
+		second := strings.Split(line, "   ")[1]
+		secondN, err := strconv.Atoi(second)
+		if err != nil {
+			log.Fatal(err)
+		}
+		a = append(a, firstN)
+		b = append(b, secondN)
+	}
+	sort.Slice(a, func(i, j int) bool {
+		return a[i] < a[j]
+	})
+	sort.Slice(b, func(i, j int) bool {
+		return b[i] < b[j]
+	})
+	for _, left := range a {
+		count := 0
+		for _, right := range b {
+			if left == right {
+				count++
+			}
+		}
+		sum += left * count
+	}
+	return sum, nil
+}
+
 func main() {
 	input, err := os.Open("input.txt")
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer input.Close()
-	sum, err := calculateDistances(input)
+	distances, err := calculateDistances(input)
+	if err != nil {
+		log.Fatal(err)
+	}
+	input.Seek(0, 0)
+	similarityScore, err := similarityScore(input)
 	if err != nil {
 		log.Fatal(err)
 	}
-	fmt.Println(sum)
+	fmt.Println(distances)
+	fmt.Println(similarityScore)
 }