feat: add swift implementation to lcof2 problem: No.024 (#3012)

Author: klever34

lcof2/剑指 Offer II 024. 反转链表/README.md

@@ -219,6 +219,38 @@ public class Solution {
 }
 ```
 
+#### Swift
+
+```swift
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     public var val: Int
+ *     public var next: ListNode?
+ *     public init(_ val: Int) {
+ *         self.val = val
+ *         self.next = nil
+ *     }
+ * }
+ */
+
+ class Solution {
+    func reverseList(_ head: ListNode?) -> ListNode? {
+        var prev: ListNode? = nil
+        var current = head
+
+        while current != nil {
+            let next = current?.next
+            current?.next = prev
+            prev = current
+            current = next
+        }
+
+        return prev
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 024. 反转链表/Solution.swift

@@ -0,0 +1,27 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     public var val: Int
+ *     public var next: ListNode?
+ *     public init(_ val: Int) {
+ *         self.val = val
+ *         self.next = nil
+ *     }
+ * }
+ */
+
+ class Solution {
+    func reverseList(_ head: ListNode?) -> ListNode? {
+        var prev: ListNode? = nil
+        var current = head
+        
+        while current != nil {
+            let next = current?.next
+            current?.next = prev
+            prev = current
+            current = next
+        }
+        
+        return prev
+    }
+}