feat: add Swift codes for hash_algorithm article (krahets#576)

codes/swift/Package.swift

@@ -29,6 +29,8 @@ let package = Package(
         .executable(name: "array_hash_map", targets: ["array_hash_map"]),
         .executable(name: "hash_map_chaining", targets: ["hash_map_chaining"]),
         .executable(name: "hash_map_open_addressing", targets: ["hash_map_open_addressing"]),
+        .executable(name: "simple_hash", targets: ["simple_hash"]),
+        .executable(name: "built_in_hash", targets: ["built_in_hash"]),
         // chapter_tree
         .executable(name: "binary_tree", targets: ["binary_tree"]),
         .executable(name: "binary_tree_bfs", targets: ["binary_tree_bfs"]),
@@ -95,6 +97,8 @@ let package = Package(
         .executableTarget(name: "array_hash_map", dependencies: ["utils"], path: "chapter_hashing", sources: ["array_hash_map.swift"]),
         .executableTarget(name: "hash_map_chaining", dependencies: ["utils"], path: "chapter_hashing", sources: ["hash_map_chaining.swift"]),
         .executableTarget(name: "hash_map_open_addressing", dependencies: ["utils"], path: "chapter_hashing", sources: ["hash_map_open_addressing.swift"]),
+        .executableTarget(name: "simple_hash", path: "chapter_hashing", sources: ["simple_hash.swift"]),
+        .executableTarget(name: "built_in_hash", dependencies: ["utils"], path: "chapter_hashing", sources: ["built_in_hash.swift"]),
         // chapter_tree
         .executableTarget(name: "binary_tree", dependencies: ["utils"], path: "chapter_tree", sources: ["binary_tree.swift"]),
         .executableTarget(name: "binary_tree_bfs", dependencies: ["utils"], path: "chapter_tree", sources: ["binary_tree_bfs.swift"]),

codes/swift/chapter_hashing/built_in_hash.swift

@@ -0,0 +1,37 @@
+/**
+ * File: built_in_hash.swift
+ * Created Time: 2023-07-01
+ * Author: nuomi1 ([email protected])
+ */
+
+import utils
+
+@main
+enum BuiltInHash {
+    /* Driver Code */
+    static func main() {
+        let num = 3
+        let hashNum = num.hashValue
+        print("整数 \(num) 的哈希值为 \(hashNum)")
+
+        let bol = true
+        let hashBol = bol.hashValue
+        print("布尔量 \(bol) 的哈希值为 \(hashBol)")
+
+        let dec = 3.14159
+        let hashDec = dec.hashValue
+        print("小数 \(dec) 的哈希值为 \(hashDec)")
+
+        let str = "Hello 算法"
+        let hashStr = str.hashValue
+        print("字符串 \(str) 的哈希值为 \(hashStr)")
+
+        let arr = [AnyHashable(12836), AnyHashable("小哈")]
+        let hashTup = arr.hashValue
+        print("数组 \(arr) 的哈希值为 \(hashTup)")
+
+        let obj = ListNode(x: 0)
+        let hashObj = obj.hashValue
+        print("节点对象 \(obj) 的哈希值为 \(hashObj)")
+    }
+}

codes/swift/chapter_hashing/simple_hash.swift

@@ -0,0 +1,73 @@
+/**
+ * File: simple_hash.swift
+ * Created Time: 2023-07-01
+ * Author: nuomi1 ([email protected])
+ */
+
+/* 加法哈希 */
+func addHash(key: String) -> Int {
+    var hash = 0
+    let MODULUS = 1_000_000_007
+    for c in key {
+        for scalar in c.unicodeScalars {
+            hash = (hash + Int(scalar.value)) % MODULUS
+        }
+    }
+    return hash
+}
+
+/* 乘法哈希 */
+func mulHash(key: String) -> Int {
+    var hash = 0
+    let MODULUS = 1_000_000_007
+    for c in key {
+        for scalar in c.unicodeScalars {
+            hash = (31 * hash + Int(scalar.value)) % MODULUS
+        }
+    }
+    return hash
+}
+
+/* 异或哈希 */
+func xorHash(key: String) -> Int {
+    var hash = 0
+    let MODULUS = 1_000_000_007
+    for c in key {
+        for scalar in c.unicodeScalars {
+            hash ^= Int(scalar.value)
+        }
+    }
+    return hash & MODULUS
+}
+
+/* 旋转哈希 */
+func rotHash(key: String) -> Int {
+    var hash = 0
+    let MODULUS = 1_000_000_007
+    for c in key {
+        for scalar in c.unicodeScalars {
+            hash = ((hash << 4) ^ (hash >> 28) ^ Int(scalar.value)) % MODULUS
+        }
+    }
+    return hash
+}
+
+@main
+enum SimpleHash {
+    /* Driver Code */
+    static func main() {
+        let key = "Hello 算法"
+
+        var hash = addHash(key: key)
+        print("加法哈希值为 \(hash)")
+
+        hash = mulHash(key: key)
+        print("乘法哈希值为 \(hash)")
+
+        hash = xorHash(key: key)
+        print("异或哈希值为 \(hash)")
+
+        hash = rotHash(key: key)
+        print("旋转哈希值为 \(hash)")
+    }
+}

codes/swift/utils/ListNode.swift

@@ -4,14 +4,23 @@
  * Author: nuomi1 ([email protected])
  */
 
-public class ListNode {
+public class ListNode: Hashable {
     public var val: Int // 节点值
     public var next: ListNode? // 后继节点引用
 
     public init(x: Int) {
         val = x
     }
 
+    public static func == (lhs: ListNode, rhs: ListNode) -> Bool {
+        lhs.val == rhs.val && lhs.next.map { ObjectIdentifier($0) } == rhs.next.map { ObjectIdentifier($0) }
+    }
+
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(val)
+        hasher.combine(next.map { ObjectIdentifier($0) })
+    }
+
     public static func arrToLinkedList(arr: [Int]) -> ListNode? {
         let dum = ListNode(x: 0)
         var head: ListNode? = dum