From 5da3bbfefecf6d51da71171e0c366416cb95fd17 Mon Sep 17 00:00:00 2001
From: YDZ <ydz627@gmail.com>
Date: Fri, 17 May 2019 08:25:33 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20problem=20110?=
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---
 .../110. Balanced Binary Tree.go              | 25 +++++++
 .../110. Balanced Binary Tree_test.go         | 74 +++++++++++++++++++
 .../110. Balanced Binary Tree/README.md       | 50 +++++++++++++
 3 files changed, 149 insertions(+)
 create mode 100644 Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree.go
 create mode 100644 Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree_test.go
 create mode 100644 Algorithms/110. Balanced Binary Tree/README.md

diff --git a/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree.go b/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree.go
new file mode 100644
index 00000000..d7018c32
--- /dev/null
+++ b/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree.go	
@@ -0,0 +1,25 @@
+package leetcode
+
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func isBalanced(root *TreeNode) bool {
+	if root == nil {
+		return true
+	}
+	leftHight := depth(root.Left)
+	rightHight := depth(root.Right)
+	return abs(leftHight-rightHight) <= 1 && isBalanced(root.Left) && isBalanced(root.Right)
+}
+
+func depth(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+	return max(depth(root.Left), depth(root.Right)) + 1
+}
diff --git a/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree_test.go b/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree_test.go
new file mode 100644
index 00000000..9e8b4ae7
--- /dev/null
+++ b/Algorithms/110. Balanced Binary Tree/110. Balanced Binary Tree_test.go	
@@ -0,0 +1,74 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question110 struct {
+	para110
+	ans110
+}
+
+// para 是参数
+// one 代表第一个参数
+type para110 struct {
+	one []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans110 struct {
+	one bool
+}
+
+func Test_Problem110(t *testing.T) {
+
+	qs := []question110{
+
+		question110{
+			para110{[]int{3, 4, 4, 5, NULL, NULL, 5, 6, NULL, NULL, 6}},
+			ans110{false},
+		},
+
+		question110{
+			para110{[]int{1, 2, 2, NULL, 3, 3}},
+			ans110{true},
+		},
+
+		question110{
+			para110{[]int{}},
+			ans110{true},
+		},
+
+		question110{
+			para110{[]int{1}},
+			ans110{true},
+		},
+
+		question110{
+			para110{[]int{1, 2, 3}},
+			ans110{true},
+		},
+
+		question110{
+			para110{[]int{1, 2, 2, 3, 4, 4, 3}},
+			ans110{true},
+		},
+
+		question110{
+			para110{[]int{1, 2, 2, NULL, 3, NULL, 3}},
+			ans110{true},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 110------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans110, q.para110
+		fmt.Printf("【input】:%v      ", p)
+		rootOne := Ints2TreeNode(p.one)
+		fmt.Printf("【output】:%v      \n", isBalanced(rootOne))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/Algorithms/110. Balanced Binary Tree/README.md b/Algorithms/110. Balanced Binary Tree/README.md
new file mode 100644
index 00000000..bae382e7
--- /dev/null
+++ b/Algorithms/110. Balanced Binary Tree/README.md	
@@ -0,0 +1,50 @@
+# [110. Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/)
+
+## 题目
+
+
+Given a binary tree, determine if it is height-balanced.
+
+For this problem, a height-balanced binary tree is defined as:
+
+a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
+
+Example 1:
+
+Given the following tree [3,9,20,null,null,15,7]:
+
+```c
+    3
+   / \
+  9  20
+    /  \
+   15   7
+```
+
+Return true.
+
+Example 2:
+
+Given the following tree [1,2,2,3,3,null,null,4,4]:
+
+
+```c
+       1
+      / \
+     2   2
+    / \
+   3   3
+  / \
+ 4   4
+```
+
+Return false.
+
+
+## 题目大意
+
+判断一棵树是不是平衡二叉树。平衡二叉树的定义是：树中每个节点都满足左右两个子树的高度差 <= 1 的这个条件。
+
+计算树的高度是第 104 题。
+
+