update README

Author: forgeyao

README.md

@@ -38,9 +38,9 @@ LeetCode
 |119|[杨辉三角 II](https://leetcode-cn.com/problems/pascals-triangle-ii/)|[Go](./119/119-getRow.go)|简单||
 |121|[买卖股票的最佳时机](https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock/)|[Go](./121/121-maxProfit.go)|简单||
 |122|[买卖股票的最佳时机 II](https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii/)|[Go](./122/122-maxProfit.go)|简单|贪心|
-|136|[只出现一次的数字](https://leetcode-cn.com/problems/single-number/)|[Go](./136/136-singleNumber.go)|简单|位运算|
 |125|[验证回文串](https://leetcode-cn.com/problems/valid-palindrome/)|[Go](./125-isPalindrome/125-isPalindrome.go)|简单||
 |131|[分割回文串](https://leetcode-cn.com/problems/palindrome-partitioning/) | [Go](./131-partition/131-partition.go)|中等|递归, 动态规划|
+|136|[只出现一次的数字](https://leetcode-cn.com/problems/single-number/)|[Go](./136/136-singleNumber.go)|简单|位运算|
 |141|[环形链表](https://leetcode-cn.com/problems/linked-list-cycle/)|[Go](./141-hasCycle/141-hasCycle.go)|简单|双指针|
 |234|[回文链表](https://leetcode-cn.com/problems/palindrome-linked-list/)|[Go](./234-isPalindrome/234-isPalindrome.go)|简单|链表|
 |206|[反转链表](https://leetcode-cn.com/problems/reverse-linked-list/)|[Go](./206-reverseList/206-reverseList.go)|简单|链表|