diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index a9d754e..4f3f6d0 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -1,8 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ChangeListManager">
-    <list default="true" id="af7ffdf2-4ddc-4ed6-8222-60ed5acbc2ed" name="Default Changelist" comment="add q215/q347">
-      <change afterPath="$PROJECT_DIR$/src/栈相关/q316_去除重复字母/Solution.java" afterDir="false" />
+    <list default="true" id="af7ffdf2-4ddc-4ed6-8222-60ed5acbc2ed" name="Default Changelist" comment="add q316">
+      <change afterPath="$PROJECT_DIR$/src/递归/q226_翻转二叉树/Solution.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/递归/q226_翻转二叉树/TreeNode.java" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/README.md" beforeDir="false" afterPath="$PROJECT_DIR$/README.md" afterDir="false" />
     </list>
@@ -67,11 +68,11 @@
   </component>
   <component name="RecentsManager">
     <key name="CopyClassDialog.RECENTS_KEY">
+      <recent name="递归.q226_翻转二叉树" />
       <recent name="链表操作.q138_复制带随机指针的链表.f2" />
       <recent name="链表操作.q138_复制带随机指针的链表.f1" />
       <recent name="hash相关.q141_环形链表.f2" />
       <recent name="hash相关.q141_环形链表.f1" />
-      <recent name="树的遍历.q102_二叉树的层次遍历" />
     </key>
     <key name="CopyFile.RECENT_KEYS">
       <recent name="$PROJECT_DIR$/src/hash相关" />
@@ -281,7 +282,8 @@
       <workItem from="1582873496305" duration="10718000" />
       <workItem from="1583244406273" duration="200000" />
       <workItem from="1583480518824" duration="4257000" />
-      <workItem from="1583497707004" duration="98000" />
+      <workItem from="1583497707004" duration="210000" />
+      <workItem from="1583849488567" duration="658000" />
     </task>
     <task id="LOCAL-00001" summary="add q5/q7/q172">
       <created>1580045439607</created>
@@ -605,7 +607,14 @@
       <option name="project" value="LOCAL" />
       <updated>1582972061183</updated>
     </task>
-    <option name="localTasksCounter" value="47" />
+    <task id="LOCAL-00047" summary="add q316">
+      <created>1583497819094</created>
+      <option name="number" value="00047" />
+      <option name="presentableId" value="LOCAL-00047" />
+      <option name="project" value="LOCAL" />
+      <updated>1583497819094</updated>
+    </task>
+    <option name="localTasksCounter" value="48" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
@@ -658,7 +667,6 @@
     </option>
   </component>
   <component name="VcsManagerConfiguration">
-    <MESSAGE value="add q53" />
     <MESSAGE value="add q54" />
     <MESSAGE value="add q23/q101" />
     <MESSAGE value="add q94/98/144/145" />
@@ -683,7 +691,8 @@
     <MESSAGE value="add q138" />
     <MESSAGE value="add q56" />
     <MESSAGE value="add q215/q347" />
-    <option name="LAST_COMMIT_MESSAGE" value="add q215/q347" />
+    <MESSAGE value="add q316" />
+    <option name="LAST_COMMIT_MESSAGE" value="add q316" />
   </component>
   <component name="WindowStateProjectService">
     <state x="320" y="115" key="#Inspections" timestamp="1581061018990">
@@ -698,10 +707,10 @@
       <screen x="0" y="0" width="1440" height="900" />
     </state>
     <state x="533" y="166" key="#com.intellij.ide.util.MemberChooser/0.0.1440.900@0.0.1440.900" timestamp="1578548165321" />
-    <state x="303" y="50" key="CommitChangelistDialog2" timestamp="1582979530005">
+    <state x="303" y="50" key="CommitChangelistDialog2" timestamp="1583851362092">
       <screen x="0" y="0" width="1440" height="900" />
     </state>
-    <state x="303" y="50" key="CommitChangelistDialog2/0.0.1440.900@0.0.1440.900" timestamp="1582979530005" />
+    <state x="303" y="50" key="CommitChangelistDialog2/0.0.1440.900@0.0.1440.900" timestamp="1583851362092" />
     <state x="144" y="78" width="1152" height="720" key="DiffContextDialog" timestamp="1582971909377">
       <screen x="0" y="0" width="1440" height="900" />
     </state>
@@ -756,10 +765,10 @@
       <screen x="0" y="0" width="1440" height="900" />
     </state>
     <state x="221" y="63" key="SettingsEditor/0.0.1440.900@0.0.1440.900" timestamp="1583244442349" />
-    <state x="320" y="190" key="Vcs.Push.Dialog.v2" timestamp="1582972062261">
+    <state x="320" y="190" key="Vcs.Push.Dialog.v2" timestamp="1583497821216">
       <screen x="0" y="0" width="1440" height="900" />
     </state>
-    <state x="320" y="190" key="Vcs.Push.Dialog.v2/0.0.1440.900@0.0.1440.900" timestamp="1582972062261" />
+    <state x="320" y="190" key="Vcs.Push.Dialog.v2/0.0.1440.900@0.0.1440.900" timestamp="1583497821216" />
     <state x="100" y="100" width="1240" height="700" key="com.intellij.history.integration.ui.views.DirectoryHistoryDialog" timestamp="1581744794182">
       <screen x="0" y="23" width="1440" height="797" />
     </state>
diff --git a/README.md b/README.md
index 4f03271..987624d 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,7 @@
 
 * [q21_合并两个有序链表](/src/递归/q21_合并两个有序链表)
 * [q101_对称二叉树](/src/递归/q101_对称二叉树)
+* [q226_翻转二叉树](/src/递归/q226_翻转二叉树)
 * [q236_二叉树的最近公共祖先](/src/递归/q236_二叉树的最近公共祖先)
 
 ### 分治法/二分法
diff --git a/src/递归/q226_翻转二叉树/Solution.java b/src/递归/q226_翻转二叉树/Solution.java
new file mode 100644
index 0000000..2d17d88
--- /dev/null
+++ b/src/递归/q226_翻转二叉树/Solution.java
@@ -0,0 +1,23 @@
+package 递归.q226_翻转二叉树;
+
+/**
+ * 递归 o(n)
+ */
+public class Solution {
+
+    public TreeNode invertTree(TreeNode root) {
+        if (root == null) {
+            return null;
+        }
+        TreeNode temp = root.left;
+        root.left = root.right;
+        root.right = temp;
+        if (root.left != null) {
+            invertTree(root.left);
+        }
+        if (root.right != null) {
+            invertTree(root.right);
+        }
+        return root;
+    }
+}
diff --git a/src/递归/q226_翻转二叉树/TreeNode.java b/src/递归/q226_翻转二叉树/TreeNode.java
new file mode 100644
index 0000000..ac16744
--- /dev/null
+++ b/src/递归/q226_翻转二叉树/TreeNode.java
@@ -0,0 +1,11 @@
+package 递归.q226_翻转二叉树;
+
+public class TreeNode {
+    int val;
+    TreeNode left;
+    TreeNode right;
+
+    TreeNode(int x) {
+        val = x;
+    }
+}