feat: solve part one using basic regex parsing

internal/2015/DayTwelve/code.go

@@ -0,0 +1,35 @@
+package daytwelve
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	registry.Register("2015D12", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(string(content), "\n")
+}
+
+func PartOne(data []string) int {
+	re := regexp.MustCompile(`-?\d+`)
+	sum := 0
+	for _, line := range data {
+		matches := re.FindAllString(line, -1)
+		for _, match := range matches {
+			number, _ := strconv.Atoi(match)
+			sum += number
+		}
+	}
+	return sum
+}
+
+func PartTwo(data []string) int {
+	return 0
+}