Improved per PR notes

Signed-off-by: Slava Lysunkin <[email protected]>

Author: lysunkin

go/Two Pointers/is_palindrome_valid.go

@@ -1,7 +1,3 @@
-func isAlnum(r rune) bool {
-	return unicode.IsLetter(r) || unicode.IsDigit(r)
-}
-
 func isPalindromeValid(input string) bool {
 	s := []rune(input)
 
@@ -28,3 +24,7 @@ func isPalindromeValid(input string) bool {
 
 	return true
 }
+
+func isAlnum(r rune) bool {
+	return unicode.IsLetter(r) || unicode.IsDigit(r)
+}

go/Two Pointers/next_lexicographical_sequence.go

@@ -1,12 +1,3 @@
-func reverse(s []rune, start int) {
-	end := len(s) - 1
-	for start < end {
-		s[start], s[end] = s[end], s[start]
-		start++
-		end--
-	}
-}
-
 func nextLexicographicalSequence(s string) string {
 	letters := []rune(s)
 	// Locate the pivot, which is the first character from the right that breaks
@@ -33,3 +24,12 @@ func nextLexicographicalSequence(s string) string {
 	reverse(letters, pivot+1)
 	return string(letters)
 }
+
+func reverse(s []rune, start int) {
+	end := len(s) - 1
+	for start < end {
+		s[start], s[end] = s[end], s[start]
+		start++
+		end--
+	}
+}

go/Two Pointers/pair_sum_sorted.go

@@ -15,5 +15,5 @@ func pairSumSorted(nums []int, target int) []int {
 			return []int{left, right}
 		}
 	}
-	return []int{}
+	return nil
 }