From 0fe499ac4142d87634d43c8e447de48091b803c3 Mon Sep 17 00:00:00 2001
From: ZongqinWang <1722249371@qq.com>
Date: Wed, 25 May 2022 21:01:54 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200106.=E4=BB=8E=E4=B8=AD?=
 =?UTF-8?q?=E5=BA=8F=E4=B8=8E=E5=90=8E=E5=BA=8F=E9=81=8D=E5=8E=86=E5=BA=8F?=
 =?UTF-8?q?=E5=88=97=E6=9E=84=E9=80=A0=E4=BA=8C=E5=8F=89=E6=A0=91.md=20Sca?=
 =?UTF-8?q?la=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ...序与后序遍历序列构造二叉树.md | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/problems/0106.从中序与后序遍历序列构造二叉树.md b/problems/0106.从中序与后序遍历序列构造二叉树.md
index 188ad3cb..37a702b7 100644
--- a/problems/0106.从中序与后序遍历序列构造二叉树.md
+++ b/problems/0106.从中序与后序遍历序列构造二叉树.md
@@ -1091,7 +1091,53 @@ class Solution_0106 {
 }
 ```
 
+## Scala
 
+106 从中序与后序遍历序列构造二叉树
+
+```scala
+object Solution {
+  def buildTree(inorder: Array[Int], postorder: Array[Int]): TreeNode = {
+    // 1、如果长度为0，则直接返回null
+    var len = inorder.size
+    if (len == 0) return null
+    // 2、后序数组的最后一个元素是当前根元素
+    var rootValue = postorder(len - 1)
+    var root: TreeNode = new TreeNode(rootValue, null, null)
+    if (len == 1) return root   // 如果数组只有一个节点，就直接返回
+    // 3、在中序数组中找到切割点的索引
+    var delimiterIndex: Int = inorder.indexOf(rootValue)
+    // 4、切分数组往下迭代
+    root.left = buildTree(inorder.slice(0, delimiterIndex), postorder.slice(0, delimiterIndex))
+    root.right = buildTree(inorder.slice(delimiterIndex + 1, len), postorder.slice(delimiterIndex, len - 1))
+    root   // 返回root，return关键字可以省略
+  }
+}
+```
+
+105 从前序与中序遍历序列构造二叉树
+
+```scala
+object Solution {
+  def buildTree(preorder: Array[Int], inorder: Array[Int]): TreeNode = {
+    // 1、如果长度为0，直接返回空
+    var len = inorder.size
+    if (len == 0) return null
+    // 2、前序数组的第一个元素是当前子树根节点
+    var rootValue = preorder(0)
+    var root = new TreeNode(rootValue, null, null)
+    if (len == 1) return root // 如果数组元素只有一个，那么返回根节点
+    // 3、在中序数组中，找到切割点
+    var delimiterIndex = inorder.indexOf(rootValue)
+
+    // 4、切分数组往下迭代
+    root.left = buildTree(preorder.slice(1, delimiterIndex + 1), inorder.slice(0, delimiterIndex))
+    root.right = buildTree(preorder.slice(delimiterIndex + 1, preorder.size), inorder.slice(delimiterIndex + 1, len))
+
+    root
+  }
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>