Expand benchmarking and optimize problem 9

Author: korverdev

9.go

@@ -6,6 +6,10 @@ import (
 )
 
 func isPalindrome(x int) bool {
+	if x < 0 {
+		return false
+	}
+
 	x_str := strconv.Itoa(x)
 	length_of_x := len(x_str)
 

9_test.go

@@ -32,7 +32,9 @@ func TestIsPalindrome3(t *testing.T) {
 }
 
 func BenchmarkIsPalindrome(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	midpoint := b.N / 2
+
+	for i := -midpoint; i < midpoint; i++ {
 		isPalindrome(b.N)
 	}
 }