feat: add Swift codes for stack article

codes/swift/Package.swift

@@ -13,6 +13,9 @@ let package = Package(
         .executable(name: "linked_list", targets: ["linked_list"]),
         .executable(name: "list", targets: ["list"]),
         .executable(name: "my_list", targets: ["my_list"]),
+        .executable(name: "stack", targets: ["stack"]),
+        .executable(name: "linkedlist_stack", targets: ["linkedlist_stack"]),
+        .executable(name: "array_stack", targets: ["array_stack"]),
     ],
     targets: [
         .target(name: "utils", path: "utils"),
@@ -24,5 +27,8 @@ let package = Package(
         .executableTarget(name: "linked_list", dependencies: ["utils"], path: "chapter_array_and_linkedlist", sources: ["linked_list.swift"]),
         .executableTarget(name: "list", path: "chapter_array_and_linkedlist", sources: ["list.swift"]),
         .executableTarget(name: "my_list", path: "chapter_array_and_linkedlist", sources: ["my_list.swift"]),
+        .executableTarget(name: "stack", path: "chapter_stack_and_queue", sources: ["stack.swift"]),
+        .executableTarget(name: "linkedlist_stack", dependencies: ["utils"], path: "chapter_stack_and_queue", sources: ["linkedlist_stack.swift"]),
+        .executableTarget(name: "array_stack", path: "chapter_stack_and_queue", sources: ["array_stack.swift"]),
     ]
 )

codes/swift/chapter_stack_and_queue/array_stack.swift

@@ -0,0 +1,84 @@
+/**
+ * File: array_stack.swift
+ * Created Time: 2023-01-09
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+/* 基于数组实现的栈 */
+class ArrayStack {
+    private var stack: [Int]
+
+    init() {
+        // 初始化列表（动态数组）
+        stack = []
+    }
+
+    /* 获取栈的长度 */
+    func size() -> Int {
+        stack.count
+    }
+
+    /* 判断栈是否为空 */
+    func isEmpty() -> Bool {
+        stack.isEmpty
+    }
+
+    /* 入栈 */
+    func push(num: Int) {
+        stack.append(num)
+    }
+
+    /* 出栈 */
+    func pop() -> Int {
+        if stack.isEmpty {
+            fatalError("栈为空")
+        }
+        return stack.removeLast()
+    }
+
+    /* 访问栈顶元素 */
+    func peek() -> Int {
+        if stack.isEmpty {
+            fatalError("栈为空")
+        }
+        return stack.last!
+    }
+
+    /* 将 List 转化为 Array 并返回 */
+    func toArray() -> [Int] {
+        stack
+    }
+}
+
+@main
+enum _ArrayStack {
+    /* Driver Code */
+    static func main() {
+        /* 初始化栈 */
+        let stack = ArrayStack()
+
+        /* 元素入栈 */
+        stack.push(num: 1)
+        stack.push(num: 3)
+        stack.push(num: 2)
+        stack.push(num: 5)
+        stack.push(num: 4)
+        print("栈 stack = \(stack.toArray())")
+
+        /* 访问栈顶元素 */
+        let peek = stack.peek()
+        print("栈顶元素 peek = \(peek)")
+
+        /* 元素出栈 */
+        let pop = stack.pop()
+        print("出栈元素 pop = \(pop)，出栈后 stack = \(stack.toArray())")
+
+        /* 获取栈的长度 */
+        let size = stack.size()
+        print("栈的长度 size = \(size)")
+
+        /* 判断是否为空 */
+        let isEmpty = stack.isEmpty()
+        print("栈是否为空 = \(isEmpty)")
+    }
+}

codes/swift/chapter_stack_and_queue/linkedlist_stack.swift

@@ -0,0 +1,93 @@
+/**
+ * File: linkedlist_stack.swift
+ * Created Time: 2023-01-09
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+import utils
+
+/* 基于链表实现的栈 */
+class LinkedListStack {
+    private var _peek: ListNode? // 将头结点作为栈顶
+    private var _size = 0 // 栈的长度
+
+    init() {}
+
+    /* 获取栈的长度 */
+    func size() -> Int {
+        _size
+    }
+
+    /* 判断栈是否为空 */
+    func isEmpty() -> Bool {
+        _size == 0
+    }
+
+    /* 入栈 */
+    func push(num: Int) {
+        let node = ListNode(x: num)
+        node.next = _peek
+        _peek = node
+        _size += 1
+    }
+
+    /* 出栈 */
+    func pop() -> Int {
+        let num = peek()
+        _peek = _peek?.next
+        _size -= 1
+        return num
+    }
+
+    /* 访问栈顶元素 */
+    func peek() -> Int {
+        if _size == 0 {
+            fatalError("栈为空")
+        }
+        return _peek!.val
+    }
+
+    /* 将 List 转化为 Array 并返回 */
+    func toArray() -> [Int] {
+        var node = _peek
+        var res = Array(repeating: 0, count: _size)
+        for i in sequence(first: res.count - 1, next: { $0 >= 0 + 1 ? $0 - 1 : nil }) {
+            res[i] = node!.val
+            node = node?.next
+        }
+        return res
+    }
+}
+
+@main
+enum _LinkedListStack {
+    /* Driver Code */
+    static func main() {
+        /* 初始化栈 */
+        let stack = LinkedListStack()
+
+        /* 元素入栈 */
+        stack.push(num: 1)
+        stack.push(num: 3)
+        stack.push(num: 2)
+        stack.push(num: 5)
+        stack.push(num: 4)
+        print("栈 stack = \(stack.toArray())")
+
+        /* 访问栈顶元素 */
+        let peek = stack.peek()
+        print("栈顶元素 peek = \(peek)")
+
+        /* 元素出栈 */
+        let pop = stack.pop()
+        print("出栈元素 pop = \(pop)，出栈后 stack = \(stack.toArray())")
+
+        /* 获取栈的长度 */
+        let size = stack.size()
+        print("栈的长度 size = \(size)")
+
+        /* 判断是否为空 */
+        let isEmpty = stack.isEmpty()
+        print("栈是否为空 = \(isEmpty)")
+    }
+}

codes/swift/chapter_stack_and_queue/stack.swift

@@ -0,0 +1,39 @@
+/**
+ * File: stack.swift
+ * Created Time: 2023-01-09
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+@main
+enum Stack {
+    /* Driver Code */
+    static func main() {
+        /* 初始化栈 */
+        // Swift 没有内置的栈类，可以把 Array 当作栈来使用
+        var stack: [Int] = []
+
+        /* 元素入栈 */
+        stack.append(1)
+        stack.append(3)
+        stack.append(2)
+        stack.append(5)
+        stack.append(4)
+        print("栈 stack = \(stack)")
+
+        /* 访问栈顶元素 */
+        let peek = stack.last!
+        print("栈顶元素 peek = \(peek)")
+
+        /* 元素出栈 */
+        let pop = stack.removeLast()
+        print("出栈元素 pop = \(pop)，出栈后 stack = \(stack)")
+
+        /* 获取栈的长度 */
+        let size = stack.count
+        print("栈的长度 size = \(size)")
+
+        /* 判断是否为空 */
+        let isEmpty = stack.isEmpty
+        print("栈是否为空 = \(isEmpty)")
+    }
+}

docs/chapter_stack_and_queue/stack.md

@@ -231,7 +231,28 @@ comments: true
 === "Swift"
 
     ```swift title="stack.swift"
+    /* 初始化栈 */
+    // Swift 没有内置的栈类，可以把 Array 当作栈来使用
+    var stack: [Int] = []
+
+    /* 元素入栈 */
+    stack.append(1)
+    stack.append(3)
+    stack.append(2)
+    stack.append(5)
+    stack.append(4)
 
+    /* 访问栈顶元素 */
+    let peek = stack.last!
+
+    /* 元素出栈 */
+    let pop = stack.removeLast()
+
+    /* 获取栈的长度 */
+    let size = stack.count
+
+    /* 判断是否为空 */
+    let isEmpty = stack.isEmpty
     ```
 
 ## 栈的实现
@@ -606,7 +627,58 @@ comments: true
 === "Swift"
 
     ```swift title="linkedlist_stack.swift"
+    /* 基于链表实现的栈 */
+    class LinkedListStack {
+        private var _peek: ListNode? // 将头结点作为栈顶
+        private var _size = 0 // 栈的长度
+
+        init() {}
+
+        /* 获取栈的长度 */
+        func size() -> Int {
+            _size
+        }
+
+        /* 判断栈是否为空 */
+        func isEmpty() -> Bool {
+            _size == 0
+        }
 
+        /* 入栈 */
+        func push(num: Int) {
+            let node = ListNode(x: num)
+            node.next = _peek
+            _peek = node
+            _size += 1
+        }
+
+        /* 出栈 */
+        func pop() -> Int {
+            let num = peek()
+            _peek = _peek?.next
+            _size -= 1
+            return num
+        }
+
+        /* 访问栈顶元素 */
+        func peek() -> Int {
+            if _size == 0 {
+                fatalError("栈为空")
+            }
+            return _peek!.val
+        }
+
+        /* 将 List 转化为 Array 并返回 */
+        func toArray() -> [Int] {
+            var node = _peek
+            var res = Array(repeating: 0, count: _size)
+            for i in sequence(first: res.count - 1, next: { $0 >= 0 + 1 ? $0 - 1 : nil }) {
+                res[i] = node!.val
+                node = node?.next
+            }
+            return res
+        }
+    }
     ```
 
 ### 基于数组的实现
@@ -897,7 +969,51 @@ comments: true
 === "Swift"
 
     ```swift title="array_stack.swift"
+    /* 基于数组实现的栈 */
+    class ArrayStack {
+        private var stack: [Int]
 
+        init() {
+            // 初始化列表（动态数组）
+            stack = []
+        }
+
+        /* 获取栈的长度 */
+        func size() -> Int {
+            stack.count
+        }
+
+        /* 判断栈是否为空 */
+        func isEmpty() -> Bool {
+            stack.isEmpty
+        }
+
+        /* 入栈 */
+        func push(num: Int) {
+            stack.append(num)
+        }
+
+        /* 出栈 */
+        func pop() -> Int {
+            if stack.isEmpty {
+                fatalError("栈为空")
+            }
+            return stack.removeLast()
+        }
+
+        /* 访问栈顶元素 */
+        func peek() -> Int {
+            if stack.isEmpty {
+                fatalError("栈为空")
+            }
+            return stack.last!
+        }
+
+        /* 将 List 转化为 Array 并返回 */
+        func toArray() -> [Int] {
+            stack
+        }
+    }
     ```
 
 !!! tip