From 9412e2e40529db526bbb16de1f3a9c45cf2c3949 Mon Sep 17 00:00:00 2001
From: ZongqinWang <1722249371@qq.com>
Date: Fri, 27 May 2022 17:01:56 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200700.=E4=BA=8C?=
=?UTF-8?q?=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91=E4=B8=AD=E7=9A=84=E6=90=9C?=
=?UTF-8?q?=E7=B4=A2.md=20Scala=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
problems/0700.二叉搜索树中的搜索.md | 27 ++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/problems/0700.二叉搜索树中的搜索.md b/problems/0700.二叉搜索树中的搜索.md
index 40cf4ea1..16ddef9b 100644
--- a/problems/0700.二叉搜索树中的搜索.md
+++ b/problems/0700.二叉搜索树中的搜索.md
@@ -363,7 +363,34 @@ function searchBST(root: TreeNode | null, val: number): TreeNode | null {
};
```
+## Scala
+递归:
+```scala
+object Solution {
+ def searchBST(root: TreeNode, value: Int): TreeNode = {
+ if (root == null || value == root.value) return root
+ // 相当于三元表达式，在Scala中if...else有返回值
+ if (value < root.value) searchBST(root.left, value) else searchBST(root.right, value)
+ }
+}
+```
+
+迭代:
+```scala
+object Solution {
+ def searchBST(root: TreeNode, value: Int): TreeNode = {
+ // 因为root是不可变量，所以需要赋值给一个可变量
+ var node = root
+ while (node != null) {
+ if (value < node.value) node = node.left
+ else if (value > node.value) node = node.right
+ else return node
+ }
+ null // 没有返回就返回空
+ }
+}
+```
-----------------------
From d4a4eda4b8396603a70871ff215b48b2d17eef93 Mon Sep 17 00:00:00 2001
From: ZongqinWang <1722249371@qq.com>
Date: Fri, 27 May 2022 17:29:44 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200098.=E9=AA=8C?=
=?UTF-8?q?=E8=AF=81=E4=BA=8C=E5=8F=89=E6=90=9C=E7=B4=A2=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
---
problems/0098.验证二叉搜索树.md | 43 ++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/problems/0098.验证二叉搜索树.md b/problems/0098.验证二叉搜索树.md
index a8f3c324..06f1b8d1 100644
--- a/problems/0098.验证二叉搜索树.md
+++ b/problems/0098.验证二叉搜索树.md
@@ -589,7 +589,50 @@ function isValidBST(root: TreeNode | null): boolean {
};
```
+## Scala
+辅助数组解决:
+```scala
+object Solution {
+ import scala.collection.mutable
+ def isValidBST(root: TreeNode): Boolean = {
+ var arr = new mutable.ArrayBuffer[Int]()
+ // 递归中序遍历二叉树，将节点添加到arr
+ def traversal(node: TreeNode): Unit = {
+ if (node == null) return
+ traversal(node.left)
+ arr.append(node.value)
+ traversal(node.right)
+ }
+ traversal(root)
+ // 这个数组如果是升序就代表是二叉搜索树
+ for (i <- 1 until arr.size) {
+ if (arr(i) <= arr(i - 1)) return false
+ }
+ true
+ }
+}
+```
+
+递归中解决:
+```scala
+object Solution {
+ def isValidBST(root: TreeNode): Boolean = {
+ var flag = true
+ var preValue:Long = Long.MinValue // 这里要使用Long类型
+
+ def traversal(node: TreeNode): Unit = {
+ if (node == null || flag == false) return
+ traversal(node.left)
+ if (node.value > preValue) preValue = node.value
+ else flag = false
+ traversal(node.right)
+ }
+ traversal(root)
+ flag
+ }
+}
+```
-----------------------
