feat: add Swift codes for selection_sort article (#519)

codes/swift/Package.swift

@@ -47,6 +47,7 @@ let package = Package(
         .executable(name: "linear_search", targets: ["linear_search"]),
         .executable(name: "hashing_search", targets: ["hashing_search"]),
         // chapter_sorting
+        .executable(name: "selection_sort", targets: ["selection_sort"]),
         .executable(name: "bubble_sort", targets: ["bubble_sort"]),
         .executable(name: "insertion_sort", targets: ["insertion_sort"]),
         .executable(name: "quick_sort", targets: ["quick_sort"]),
@@ -109,6 +110,7 @@ let package = Package(
         .executableTarget(name: "linear_search", dependencies: ["utils"], path: "chapter_searching", sources: ["linear_search.swift"]),
         .executableTarget(name: "hashing_search", dependencies: ["utils"], path: "chapter_searching", sources: ["hashing_search.swift"]),
         // chapter_sorting
+        .executableTarget(name: "selection_sort", path: "chapter_sorting", sources: ["selection_sort.swift"]),
         .executableTarget(name: "bubble_sort", path: "chapter_sorting", sources: ["bubble_sort.swift"]),
         .executableTarget(name: "insertion_sort", path: "chapter_sorting", sources: ["insertion_sort.swift"]),
         .executableTarget(name: "quick_sort", path: "chapter_sorting", sources: ["quick_sort.swift"]),

codes/swift/chapter_sorting/selection_sort.swift

@@ -0,0 +1,31 @@
+/**
+ * File: selection_sort.swift
+ * Created Time: 2023-05-28
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+/* 选择排序 */
+func selectionSort(nums: inout [Int]) {
+    // 外循环：未排序区间为 [i, n-1]
+    for i in nums.indices.dropLast() {
+        // 内循环：找到未排序区间内的最小元素
+        var k = i
+        for j in nums.indices.dropFirst(i + 1) {
+            if nums[j] < nums[k] {
+                k = j // 记录最小元素的索引
+            }
+        }
+        // 将该最小元素与未排序区间的首个元素交换
+        nums.swapAt(i, k)
+    }
+}
+
+@main
+enum SelectionSort {
+    /* Driver Code */
+    static func main() {
+        var nums = [4, 1, 3, 1, 5, 2]
+        selectionSort(nums: &nums)
+        print("选择排序完成后 nums = \(nums)")
+    }
+}