optimize sorting, fix a bug (#15)

pkg/utils/utils.go

@@ -114,3 +114,40 @@ func Itoa[T constraints.Integer](i T) string {
 		return ""
 	}
 }
+
+// From go1.23
+
+// Compare returns
+//
+//	-1 if x is less than y,
+//	 0 if x equals y,
+//	+1 if x is greater than y.
+//
+// For floating-point types, a NaN is considered less than any non-NaN,
+// a NaN is considered equal to a NaN, and -0.0 is equal to 0.0.
+func Compare[T constraints.Ordered](x, y T) int {
+	xNaN := isNaN(x)
+	yNaN := isNaN(y)
+	if xNaN {
+		if yNaN {
+			return 0
+		}
+		return -1
+	}
+	if yNaN {
+		return +1
+	}
+	if x < y {
+		return -1
+	}
+	if x > y {
+		return +1
+	}
+	return 0
+}
+
+// isNaN reports whether x is a NaN without requiring the math package.
+// This will always return false if T is not floating-point.
+func isNaN[T constraints.Ordered](x T) bool {
+	return x != x
+}