From 63ad545c64202b21dfbdb6f6d149799ea0b0c27f Mon Sep 17 00:00:00 2001
From: qiuxuewei <qiuxuewei@baidu.com>
Date: Wed, 24 Nov 2021 15:33:59 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20232.=E7=94=A8=E6=A0=88?=
 =?UTF-8?q?=E5=AE=9E=E7=8E=B0=E9=98=9F=E5=88=97=20Swift=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 | 37 +++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/problems/0232.用栈实现队列.md b/problems/0232.用栈实现队列.md
index 0e4a5d6d..6e247d1d 100644
--- a/problems/0232.用栈实现队列.md
+++ b/problems/0232.用栈实现队列.md
@@ -349,6 +349,43 @@ MyQueue.prototype.empty = function() {
 };
  ```
 
+Swift：
+```swift
+class MyQueue {
+    
+    var stackIn = [Int]()
+    var stackOut = [Int]()
+    
+    init() {}
+    
+    /** Push element x to the back of queue. */
+    func push(_ x: Int) {
+        stackIn.append(x)
+    }
+    
+    /** Removes the element from in front of queue and returns that element. */
+    func pop() -> Int {
+        if stackOut.isEmpty {
+            while !stackIn.isEmpty {
+                stackOut.append(stackIn.popLast()!)
+            }
+        }
+        return stackOut.popLast() ?? -1
+    }
+    
+    /** Get the front element. */
+    func peek() -> Int {
+        let res = pop()
+        stackOut.append(res)
+        return res
+    }
+    
+    /** Returns whether the queue is empty. */
+    func empty() -> Bool {
+        return stackIn.isEmpty && stackOut.isEmpty
+    }
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

From 50a12ff215f7859b512e9f4fc7154196be0f56da Mon Sep 17 00:00:00 2001
From: qiuxuewei <qiuxuewei@baidu.com>
Date: Thu, 25 Nov 2021 16:24:01 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20225.=20=E7=94=A8?=
 =?UTF-8?q?=E9=98=9F=E5=88=97=E5=AE=9E=E7=8E=B0=E6=A0=88=20Swift=E7=89=88?=
 =?UTF-8?q?=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 | 119 ++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)

diff --git a/problems/0225.用队列实现栈.md b/problems/0225.用队列实现栈.md
index edb88f36..be9f1f79 100644
--- a/problems/0225.用队列实现栈.md
+++ b/problems/0225.用队列实现栈.md
@@ -598,5 +598,124 @@ MyStack.prototype.empty = function() {
 
 ```
 
+Swift
+```Swift
+// 定义一个队列数据结构
+class Queue {
+    var array: [Int]
+    init() {
+        array = [Int]()
+    }
+    
+    /** Push element x to the back of queue. */
+    func push(_ x: Int) {
+        array.append(x)
+    }
+    
+    /** Removes the element from in front of queue and returns that element. */
+    func pop() -> Int {
+        if array.isEmpty {
+            return -1
+        }
+        return array.removeFirst()
+    }
+    
+    /** Get the front element. */
+    func peek() -> Int {
+        if array.isEmpty {
+            return -1
+        }
+        return array.first!
+    }
+    
+    /** Returns whether the queue is empty. */
+    func empty() -> Bool {
+        return array.isEmpty
+    }
+    
+    func count() -> Int {
+        return array.count
+    }
+}
+
+// 使用双队列
+class MyStack {
+    var queue1: Queue
+    var queue2: Queue
+    
+    init() {
+        queue1 = Queue()
+        queue2 = Queue()
+    }
+    
+    func push(_ x: Int) {
+        queue1.push(x)
+    }
+    
+    func pop() -> Int {
+        if queue1.empty() {
+            return -1
+        }
+        while queue1.count() > 1 {
+            queue2.push(queue1.pop())
+        }
+        let res = queue1.pop()
+        while !queue2.empty() {
+            queue1.push(queue2.pop())
+        }
+        return res
+    }
+    
+    func top() -> Int {
+        if queue1.empty() {
+            return -1
+        }
+        let res = pop()
+        push(res)
+        return res
+    }
+    
+    func empty() -> Bool {
+        return queue1.empty() && queue2.empty()
+    }
+}
+
+// 使用单队列
+class MyStack {
+    var queue: Queue
+    
+    init() {
+        queue = Queue()
+    }
+    
+    func push(_ x: Int) {
+        queue.push(x)
+    }
+    
+    func pop() -> Int {
+        if queue.empty() {
+            return -1
+        }
+        for _ in 1 ..< queue.count() {
+            queue.push(queue.pop())
+        }
+        return queue.pop()
+    }
+    
+    func top() -> Int {
+        if queue.empty() {
+            return -1
+        }
+        let res = pop()
+        push(res)
+        return res
+    }
+    
+    func empty() -> Bool {
+        return queue.empty()
+    }
+}
+```
+
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>