From 9ecd4e8ca46d02446179129e83e59228e8be8952 Mon Sep 17 00:00:00 2001
From: YDZ <ydz627@gmail.com>
Date: Sun, 26 May 2019 10:27:55 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20problem=20226?=
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---
 .../226. Invert Binary Tree.go                | 19 +++++++
 .../226. Invert Binary Tree_test.go           | 54 +++++++++++++++++++
 Algorithms/226. Invert Binary Tree/README.md  | 40 ++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 Algorithms/226. Invert Binary Tree/226. Invert Binary Tree.go
 create mode 100644 Algorithms/226. Invert Binary Tree/226. Invert Binary Tree_test.go
 create mode 100644 Algorithms/226. Invert Binary Tree/README.md

diff --git a/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree.go b/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree.go
new file mode 100644
index 00000000..e43d8b2c
--- /dev/null
+++ b/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree.go	
@@ -0,0 +1,19 @@
+package leetcode
+
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func invertTree(root *TreeNode) *TreeNode {
+	if root == nil {
+		return nil
+	}
+	invertTree(root.Left)
+	invertTree(root.Right)
+	root.Left, root.Right = root.Right, root.Left
+	return root
+}
diff --git a/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree_test.go b/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree_test.go
new file mode 100644
index 00000000..266c5f35
--- /dev/null
+++ b/Algorithms/226. Invert Binary Tree/226. Invert Binary Tree_test.go	
@@ -0,0 +1,54 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question226 struct {
+	para226
+	ans226
+}
+
+// para 是参数
+// one 代表第一个参数
+type para226 struct {
+	one []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans226 struct {
+	one []int
+}
+
+func Test_Problem226(t *testing.T) {
+
+	qs := []question226{
+
+		question226{
+			para226{[]int{}},
+			ans226{[]int{}},
+		},
+
+		question226{
+			para226{[]int{1}},
+			ans226{[]int{1}},
+		},
+
+		question226{
+			para226{[]int{4, 2, 7, 1, 3, 6, 9}},
+			ans226{[]int{4, 7, 2, 9, 6, 3, 1}},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 226------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans226, q.para226
+		fmt.Printf("【input】:%v      ", p)
+		root := Ints2TreeNode(p.one)
+		fmt.Printf("【output】:%v      \n", Tree2Preorder(invertTree(root)))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/Algorithms/226. Invert Binary Tree/README.md b/Algorithms/226. Invert Binary Tree/README.md
new file mode 100644
index 00000000..6825cdcf
--- /dev/null
+++ b/Algorithms/226. Invert Binary Tree/README.md	
@@ -0,0 +1,40 @@
+# [226. Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/)
+
+## 题目
+
+Invert a binary tree.
+
+Example:
+
+Input:
+
+```c
+     4
+   /   \
+  2     7
+ / \   / \
+1   3 6   9
+```
+
+Output:
+
+```c
+     4
+   /   \
+  7     2
+ / \   / \
+9   6 3   1
+```
+
+Trivia:   
+
+This problem was inspired by this original tweet by Max Howell:
+
+>Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so f*** off.
+ 
+
+## 题目大意
+
+"经典"的反转二叉树的问题。还是用递归来解决，先递归调用反转根节点的左孩子，然后递归调用反转根节点的右孩子，然后左右交换根节点的左孩子和右孩子。
+
+