From 08147d132c4611e190d03a47bc870294d3cc1292 Mon Sep 17 00:00:00 2001
From: ZongqinWang <1722249371@qq.com>
Date: Mon, 16 May 2022 14:28:02 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200232.=E7=94=A8?=
=?UTF-8?q?=E6=A0=88=E5=AE=9E=E7=8E=B0=E9=98=9F=E5=88=97.md=20Scala?=
=?UTF-8?q?=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
problems/0232.用栈实现队列.md | 39 +++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/problems/0232.用栈实现队列.md b/problems/0232.用栈实现队列.md
index 1a56d9f3..d9ba8e26 100644
--- a/problems/0232.用栈实现队列.md
+++ b/problems/0232.用栈实现队列.md
@@ -495,6 +495,45 @@ void myQueueFree(MyQueue* obj) {
obj->stackOutTop = 0;
}
```
+Scala:
+```scala
+class MyQueue() {
+ import scala.collection.mutable
+ val stackIn = mutable.Stack[Int]() // 负责出栈
+ val stackOut = mutable.Stack[Int]() // 负责入栈
+ // 添加元素
+ def push(x: Int) {
+ stackIn.push(x)
+ }
+
+ // 复用代码，如果stackOut为空就把stackIn的所有元素都压入StackOut
+ def dumpStackIn(): Unit = {
+ if (!stackOut.isEmpty) return
+ while (!stackIn.isEmpty) {
+ stackOut.push(stackIn.pop())
+ }
+ }
+
+ // 弹出元素
+ def pop(): Int = {
+ dumpStackIn()
+ stackOut.pop()
+ }
+
+ // 获取队头
+ def peek(): Int = {
+ dumpStackIn()
+ val res: Int = stackOut.pop()
+ stackOut.push(res)
+ res
+ }
+
+ // 判断是否为空
+ def empty(): Boolean = {
+ stackIn.isEmpty && stackOut.isEmpty
+ }
+}
+```
-----------------------
From f4d98a744ee9c14ed88d07be559aa310508d89f9 Mon Sep 17 00:00:00 2001
From: ZongqinWang <1722249371@qq.com>
Date: Mon, 16 May 2022 14:56:10 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200225.=E7=94=A8?=
=?UTF-8?q?=E9=98=9F=E5=88=97=E5=AE=9E=E7=8E=B0=E6=A0=88.md=20Scala?=
=?UTF-8?q?=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
problems/0225.用队列实现栈.md | 83 +++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/problems/0225.用队列实现栈.md b/problems/0225.用队列实现栈.md
index 3457c4b3..3c134870 100644
--- a/problems/0225.用队列实现栈.md
+++ b/problems/0225.用队列实现栈.md
@@ -815,6 +815,89 @@ class MyStack {
}
}
```
+Scala:
+使用两个队列模拟栈:
+```scala
+import scala.collection.mutable
+
+class MyStack() {
+
+ val queue1 = new mutable.Queue[Int]()
+ val queue2 = new mutable.Queue[Int]()
+
+ def push(x: Int) {
+ queue1.enqueue(x)
+ }
+
+ def pop(): Int = {
+ var size = queue1.size
+ // 将queue1中的每个元素都移动到queue2
+ for (i <- 0 until size - 1) {
+ queue2.enqueue(queue1.dequeue())
+ }
+ var res = queue1.dequeue()
+ // 再将queue2中的每个元素都移动到queue1
+ while (!queue2.isEmpty) {
+ queue1.enqueue(queue2.dequeue())
+ }
+ res
+ }
+
+ def top(): Int = {
+ var size = queue1.size
+ for (i <- 0 until size - 1) {
+ queue2.enqueue(queue1.dequeue())
+ }
+ var res = queue1.dequeue()
+ while (!queue2.isEmpty) {
+ queue1.enqueue(queue2.dequeue())
+ }
+ // 最终还需要把res送进queue1
+ queue1.enqueue(res)
+ res
+ }
+
+ def empty(): Boolean = {
+ queue1.isEmpty
+ }
+}
+```
+使用一个队列模拟:
+```scala
+import scala.collection.mutable
+
+class MyStack() {
+
+ val queue = new mutable.Queue[Int]()
+
+ def push(x: Int) {
+ queue.enqueue(x)
+ }
+
+ def pop(): Int = {
+ var size = queue.size
+ for (i <- 0 until size - 1) {
+ queue.enqueue(queue.head) // 把头添到队列最后
+ queue.dequeue() // 再出队
+ }
+ queue.dequeue()
+ }
+
+ def top(): Int = {
+ var size = queue.size
+ var res = 0
+ for (i <- 0 until size) {
+ queue.enqueue(queue.head) // 把头添到队列最后
+ res = queue.dequeue() // 再出队
+ }
+ res
+ }
+
+ def empty(): Boolean = {
+ queue.isEmpty
+ }
+}
+```
-----------------------
