Merge pull request #60 from halfrost/code_quality_improvement

optimization code quality level from A to A+

leetcode/0392.Is-Subsequence/392. Is Subsequence.go

@@ -2,9 +2,9 @@ package leetcode
 
 // 解法一 O(n^2)
 func isSubsequence(s string, t string) bool {
-	index, flag := 0, false
+	index := 0
 	for i := 0; i < len(s); i++ {
-		flag = false
+		flag := false
 		for ; index < len(t); index++ {
 			if s[i] == t[index] {
 				flag = true