添加 24. 两两交换链表中的节点 Swift版本

problems/0024.两两交换链表中的节点.md

@@ -248,6 +248,27 @@ fun swapPairs(head: ListNode?): ListNode? {
 }
 ```
 
+Swift:
+```swift
+func swapPairs(_ head: ListNode?) -> ListNode? {
+    if head == nil || head?.next == nil {
+        return head
+    }
+    let dummyHead: ListNode = ListNode(-1, head)
+    var current: ListNode? = dummyHead
+    while current?.next != nil && current?.next?.next != nil {
+        let temp1 = current?.next
+        let temp2 = current?.next?.next?.next
+        
+        current?.next = current?.next?.next
+        current?.next?.next = temp1
+        current?.next?.next?.next = temp2
+        
+        current = current?.next?.next
+    }
+    return dummyHead.next
+}
+```
 
 
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