From c15e8d34f1f58e1c2d8ab034942ae6c8e6f8338e Mon Sep 17 00:00:00 2001
From: kanna5 <kanna42@tuta.io>
Date: Tue, 9 Dec 2025 13:01:23 +0900
Subject: [PATCH] impl: q125

---
 solutions/q125/solution.go | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 solutions/q125/solution.go

diff --git a/solutions/q125/solution.go b/solutions/q125/solution.go
new file mode 100644
index 0000000..e9b33fd
--- /dev/null
+++ b/solutions/q125/solution.go
@@ -0,0 +1,32 @@
+package q125
+
+func isAlphanumeric(c byte) bool {
+	return c >= '0' && c <= '9' ||
+		c >= 'a' && c <= 'z'
+}
+
+func toLower(c byte) byte {
+	if c >= 'A' && c <= 'Z' {
+		return 'a' + c - 'A'
+	}
+	return c
+}
+
+func isPalindrome(s string) bool {
+	conv := make([]byte, 0, len(s))
+	for i := range len(s) {
+		c := toLower(s[i])
+		if isAlphanumeric(c) {
+			conv = append(conv, c)
+		}
+	}
+
+	for i := range len(conv) / 2 {
+		if conv[i] != conv[len(conv)-1-i] {
+			return false
+		}
+	}
+	return true
+}
+
+var _ = isPalindrome