From 95fa89013dd6393f4cf324184ff4c898b609d23e Mon Sep 17 00:00:00 2001
From: Copyes <fan_545697167@qq.com>
Date: Sun, 14 Jun 2020 21:59:39 +0800
Subject: [PATCH] bug fixed

---
 ScriptOJ/isBalanced.js                        |  2 +-
 ScriptOJ/isSymmetric.js                       | 23 +++++++++++++++++++
 .../\344\272\214\345\217\211\346\240\221.md"  |  1 +
 3 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 ScriptOJ/isSymmetric.js

diff --git a/ScriptOJ/isBalanced.js b/ScriptOJ/isBalanced.js
index c784781..d1316ea 100644
--- a/ScriptOJ/isBalanced.js
+++ b/ScriptOJ/isBalanced.js
@@ -17,7 +17,7 @@ var isBalanced = function(root) {
     if(node === null) return 0;
     let left = dfs(node.left);
     let right = dfs(node.right);
-    if(Math.abs(left, right) > 1) {
+    if(Math.abs(left-right) > 1) {
       ans = false;
     }
     return Math.max(left, right) + 1;
diff --git a/ScriptOJ/isSymmetric.js b/ScriptOJ/isSymmetric.js
new file mode 100644
index 0000000..e8a6822
--- /dev/null
+++ b/ScriptOJ/isSymmetric.js
@@ -0,0 +1,23 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {boolean}
+ */
+var isSymmetric = function(root) {
+  if(root == null) return true;
+  
+  function recur(L, R) {
+    if(L === null && R === null) return true;
+    if(L === null || R === null || L.val !== R.val) return false;
+    
+    return recur(L.left, R.right) && recur(L.right, R.left);
+  }
+
+  return recur(root.left, root.right);
+};
\ No newline at end of file
diff --git "a/Solutions/leetcode-solution/\344\272\214\345\217\211\346\240\221.md" "b/Solutions/leetcode-solution/\344\272\214\345\217\211\346\240\221.md"
index a82b4a9..b38d8cf 100644
--- "a/Solutions/leetcode-solution/\344\272\214\345\217\211\346\240\221.md"
+++ "b/Solutions/leetcode-solution/\344\272\214\345\217\211\346\240\221.md"
@@ -73,3 +73,4 @@ var postorderTraversal = function(root) {
 ### 题目列表
 - [x] 112. 路径总和 https://leetcode-cn.com/problems/path-sum/
 - [x] 面试题27. 二叉树的镜像 https://leetcode-cn.com/problems/er-cha-shu-de-jing-xiang-lcof/
+- [x] 面试题28. 对称的二叉树  https://leetcode-cn.com/problems/dui-cheng-de-er-cha-shu-lcof/