diff --git a/2025/day02/main.go b/2025/day02/main.go
index c3c2c7f..673c202 100644
--- a/2025/day02/main.go
+++ b/2025/day02/main.go
@@ -14,45 +14,83 @@ func main() {
 		log.Fatalf("failed to read file: %v", err)
 	}
 
-	invalidSum := 0
+	invalidSum1 := int64(0)
+	invalidSum2 := int64(0)
 
 	for rStr := range strings.SplitSeq(string(input), ",") {
 		r, err := parseRange(rStr)
 		if err != nil {
 			log.Fatalf("failed to parse range: %v", err)
 		}
-		for _, x := range r.findInvalid() {
-			invalidSum += x
+		for _, x := range r.findInvalid(false) {
+			invalidSum1 += x
+		}
+		for _, x := range r.findInvalid(true) {
+			invalidSum2 += x
 		}
 	}
 
-	fmt.Printf("part1: %d\n", invalidSum)
+	fmt.Printf("part1: %d\n", invalidSum1)
+	fmt.Printf("part2: %d\n", invalidSum2)
 }
 
 type idRange struct {
-	start int
-	end   int
+	start int64
+	end   int64
 }
 
-func (r *idRange) findInvalid() []int {
-	var invalid []int
+func (r *idRange) findInvalid(part2 bool) []int64 {
+	var invalid []int64
 	for n := r.start; n <= r.end; n++ {
-		if isRepeatedSeq(strconv.Itoa(n)) {
-			invalid = append(invalid, n)
+		if part2 {
+			if isRepeatedSeq(strconv.FormatInt(n, 10)) {
+				invalid = append(invalid, n)
+			}
+		} else {
+			if isDoubleSeq(strconv.FormatInt(n, 10)) {
+				invalid = append(invalid, n)
+			}
 		}
 	}
 	return invalid
 }
 
-func isRepeatedSeq(id string) bool {
+func isDoubleSeq(id string) bool {
 	if len(id)%2 != 0 {
 		return false
 	}
 	half := len(id) / 2
-	fmt.Printf("%s: %s | %s\n", id, id[0:half], id[half:])
 	return id[0:half] == id[half:]
 }
 
+func isRepeatedSeq(id string) bool {
+	for i := range len(id) {
+		if i == 0 || len(id)%i != 0 {
+			continue
+		}
+
+		var parts []string
+		for s := 0; s <= len(id)-i; s += i {
+			parts = append(parts, id[s:s+i])
+		}
+
+		allMatch := true
+		for p := range parts {
+			if p == 0 {
+				continue
+			}
+			if parts[p-1] != parts[p] {
+				allMatch = false
+			}
+		}
+
+		if allMatch {
+			return true
+		}
+	}
+	return false
+}
+
 func parseRange(rStr string) (idRange, error) {
 	parts := strings.Split(rStr, "-")
 	start, err := strconv.Atoi(strings.TrimSpace(parts[0]))
@@ -63,5 +101,5 @@ func parseRange(rStr string) (idRange, error) {
 	if err != nil {
 		return idRange{}, fmt.Errorf("failed to parse end %q: %w", parts[1], err)
 	}
-	return idRange{start: start, end: end}, nil
+	return idRange{start: int64(start), end: int64(end)}, nil
 }