feat: add Swift codes for deque article

codes/swift/Package.swift

@@ -19,6 +19,7 @@ let package = Package(
         .executable(name: "queue", targets: ["queue"]),
         .executable(name: "linkedlist_queue", targets: ["linkedlist_queue"]),
         .executable(name: "array_queue", targets: ["array_queue"]),
+        .executable(name: "deque", targets: ["deque"]),
     ],
     targets: [
         .target(name: "utils", path: "utils"),
@@ -36,5 +37,6 @@ let package = Package(
         .executableTarget(name: "queue", path: "chapter_stack_and_queue", sources: ["queue.swift"]),
         .executableTarget(name: "linkedlist_queue", dependencies: ["utils"], path: "chapter_stack_and_queue", sources: ["linkedlist_queue.swift"]),
         .executableTarget(name: "array_queue", path: "chapter_stack_and_queue", sources: ["array_queue.swift"]),
+        .executableTarget(name: "deque", path: "chapter_stack_and_queue", sources: ["deque.swift"]),
     ]
 )

codes/swift/chapter_stack_and_queue/deque.swift

@@ -0,0 +1,43 @@
+/**
+ * File: deque.swift
+ * Created Time: 2023-01-14
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+@main
+enum Deque {
+    /* Driver Code */
+    static func main() {
+        /* 初始化双向队列 */
+        // Swift 没有内置的双向队列类，可以把 Array 当作双向队列来使用
+        var deque: [Int] = []
+
+        /* 元素入队 */
+        deque.append(2)
+        deque.append(5)
+        deque.append(4)
+        deque.insert(3, at: 0)
+        deque.insert(1, at: 0)
+        print("双向队列 deque = \(deque)")
+
+        /* 访问元素 */
+        let peekFirst = deque.first!
+        print("队首元素 peekFirst = \(peekFirst)")
+        let peekLast = deque.last!
+        print("队尾元素 peekLast = \(peekLast)")
+
+        /* 元素出队 */
+        let pollFirst = deque.removeFirst()
+        print("队首出队元素 pollFirst = \(pollFirst)，队首出队后 deque = \(deque)")
+        let pollLast = deque.removeLast()
+        print("队尾出队元素 pollLast = \(pollLast)，队尾出队后 deque = \(deque)")
+
+        /* 获取双向队列的长度 */
+        let size = deque.count
+        print("双向队列长度 size = \(size)")
+
+        /* 判断双向队列是否为空 */
+        let isEmpty = deque.isEmpty
+        print("双向队列是否为空 = \(isEmpty)")
+    }
+}

docs/chapter_stack_and_queue/deque.md

@@ -196,5 +196,28 @@ comments: true
 === "Swift"
 
     ```swift title="deque.swift"
+    /* 初始化双向队列 */
+    // Swift 没有内置的双向队列类，可以把 Array 当作双向队列来使用
+    var deque: [Int] = []
+
+    /* 元素入队 */
+    deque.append(2) // 添加至队尾
+    deque.append(5)
+    deque.append(4)
+    deque.insert(3, at: 0) // 添加至队首
+    deque.insert(1, at: 0)
+
+    /* 访问元素 */
+    let peekFirst = deque.first! // 队首元素
+    let peekLast = deque.last! // 队尾元素
 
+    /* 元素出队 */
+    let pollFirst = deque.removeFirst() // 队首元素出队
+    let pollLast = deque.removeLast() // 队尾元素出队
+
+    /* 获取双向队列的长度 */
+    let size = deque.count
+
+    /* 判断双向队列是否为空 */
+    let isEmpty = deque.isEmpty
     ```