fix: 修改链接

Author: Mayandev

leetcode刷题/README.md

@@ -21,6 +21,7 @@
 - [No.237 删除链表节点](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No237_delete-node.md)
 - [No.242 有效的字母异位词](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No242_is-anagram.md)
 - [No.283 移动零](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No283_move-zeroes.md)
+- [No.326 3的幂](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No326_is-power-of-three.md)
 - [No.350 两个数组的交集 II](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No350_intersect.md)
 - [No.387 字符串中的第一个唯一字符](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No387_first-uniq-char.md)
 
@@ -69,3 +70,8 @@
 - [No.237 删除链表节点](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No237_delete-node.md)
 
 
+### 数学
+
+#### 数学初级
+
+- [No.326 3的幂](https://github.com/Mayandev/javascript_algorithm/blob/master/leetcode%E5%88%B7%E9%A2%98/note/No326_is-power-of-three.md)