valid-palindrome: string builder version

Author: Invidam

valid-palindrome/invidam.go

@@ -0,0 +1,16 @@
+func isPalindrome(s string) bool {
+	var sb strings.Builder
+	sb.Grow(len(s))
+	for _, ch := range s {
+		if unicode.IsLetter(ch) || unicode.IsNumber(ch) {
+			sb.WriteRune(unicode.ToLower(ch))
+		}
+	}
+	filtered := sb.String()
+	for ldx, rdx := 0, len(filtered)-1; ldx < rdx; ldx, rdx = ldx+1, rdx-1 {
+		if filtered[ldx] != filtered[rdx] {
+			return false
+		}
+	}
+	return true
+}