diff --git a/codes/swift/chapter_stack_and_queue/deque.swift b/codes/swift/chapter_stack_and_queue/deque.swift
index 205da4055..6638eacb3 100644
--- a/codes/swift/chapter_stack_and_queue/deque.swift
+++ b/codes/swift/chapter_stack_and_queue/deque.swift
@@ -27,6 +27,7 @@ enum Deque {
         print("队尾元素 peekLast = \(peekLast)")
 
         /* 元素出队 */
+        // 使用 Array 模拟时 pollFirst 的复杂度为 O(n)
         let pollFirst = deque.removeFirst()
         print("队首出队元素 pollFirst = \(pollFirst)，队首出队后 deque = \(deque)")
         let pollLast = deque.removeLast()
diff --git a/codes/swift/chapter_stack_and_queue/queue.swift b/codes/swift/chapter_stack_and_queue/queue.swift
index f13af36f5..ea1e94722 100644
--- a/codes/swift/chapter_stack_and_queue/queue.swift
+++ b/codes/swift/chapter_stack_and_queue/queue.swift
@@ -25,6 +25,7 @@ enum Queue {
         print("队首元素 peek = \(peek)")
 
         /* 元素出队 */
+        // 使用 Array 模拟时 poll 的复杂度为 O(n)
         let pool = queue.removeFirst()
         print("出队元素 poll = \(pool)，出队后 queue = \(queue)")
 
diff --git a/docs/chapter_stack_and_queue/deque.md b/docs/chapter_stack_and_queue/deque.md
index e4674d5f1..b8d4df9ad 100644
--- a/docs/chapter_stack_and_queue/deque.md
+++ b/docs/chapter_stack_and_queue/deque.md
@@ -212,6 +212,7 @@ comments: true
     let peekLast = deque.last! // 队尾元素
 
     /* 元素出队 */
+    // 使用 Array 模拟时 pollFirst 的复杂度为 O(n)
     let pollFirst = deque.removeFirst() // 队首元素出队
     let pollLast = deque.removeLast() // 队尾元素出队
 
diff --git a/docs/chapter_stack_and_queue/queue.md b/docs/chapter_stack_and_queue/queue.md
index d70b3e528..aaba7da43 100644
--- a/docs/chapter_stack_and_queue/queue.md
+++ b/docs/chapter_stack_and_queue/queue.md
@@ -246,6 +246,7 @@ comments: true
     let peek = queue.first!
 
     /* 元素出队 */
+    // 使用 Array 模拟时 poll 的复杂度为 O(n)
     let pool = queue.removeFirst()
 
     /* 获取队列的长度 */