diff --git a/datastructure/hashmap/hashmap.go b/datastructure/hashmap/hashmap.go
index 464cb38..d46e298 100644
--- a/datastructure/hashmap/hashmap.go
+++ b/datastructure/hashmap/hashmap.go
@@ -1,7 +1,7 @@
 // Copyright 2021 dudaodong@gmail.com. All rights reserved.
 // Use of this source code is governed by MIT license
 
-// Package datastructure implements some data structure. eg. list, linklist, stack, queue, tree, graph.
+// Package datastructure implements some data structure. hashmap structure.
 package datastructure
 
 import (
diff --git a/datastructure/heap/maxheap.go b/datastructure/heap/maxheap.go
index 1fa56cc..e496e14 100644
--- a/datastructure/heap/maxheap.go
+++ b/datastructure/heap/maxheap.go
@@ -1,7 +1,7 @@
 // Copyright 2021 dudaodong@gmail.com. All rights reserved.
 // Use of this source code is governed by MIT license
 
-// Package datastructure implements some data structure. eg. list, linklist, stack, queue, tree, graph.
+// Package datastructure implements some data structure. MaxHeap is a binary max heap.
 package datastructure
 
 import (
diff --git a/datastructure/link/doublylink.go b/datastructure/link/doublylink.go
index 173e6a3..4e56643 100644
--- a/datastructure/link/doublylink.go
+++ b/datastructure/link/doublylink.go
@@ -1,3 +1,7 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. Link structure contains SinglyLink and DoublyLink.
 package datastructure
 
 import (
diff --git a/datastructure/link/singlylink.go b/datastructure/link/singlylink.go
index 1b26632..401325a 100644
--- a/datastructure/link/singlylink.go
+++ b/datastructure/link/singlylink.go
@@ -1,3 +1,7 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. Link structure contains SinglyLink and DoublyLink.
 package datastructure
 
 import (
diff --git a/datastructure/list/list.go b/datastructure/list/list.go
index 97556df..2a359e4 100644
--- a/datastructure/list/list.go
+++ b/datastructure/list/list.go
@@ -1,7 +1,7 @@
 // Copyright 2021 dudaodong@gmail.com. All rights reserved.
 // Use of this source code is governed by MIT license
 
-// Package datastructure implements some data structure. eg. list, linklist, stack, queue, tree, graph.
+// Package datastructure contains some data structure. list is a linear table, implemented with slice.
 package datastructure
 
 import (
diff --git a/datastructure/node.go b/datastructure/node.go
index 0910cef..ed24a83 100644
--- a/datastructure/node.go
+++ b/datastructure/node.go
@@ -1,7 +1,7 @@
 // Copyright 2021 dudaodong@gmail.com. All rights reserved.
 // Use of this source code is governed by MIT license
 
-// Package datastructure implements some data structure. eg. list, linklist, stack, queue, tree, graph.
+// Package datastructure implements some data structure.
 package datastructure
 
 // LinkNode is a linkedlist node, which have a Value and Pre points to previous node, Next points to a next node of the link.
diff --git a/datastructure/queue/arrayqueue.go b/datastructure/queue/arrayqueue.go
index 27079b4..fd5d13d 100644
--- a/datastructure/queue/arrayqueue.go
+++ b/datastructure/queue/arrayqueue.go
@@ -1,3 +1,8 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure.
+// Queue structure contains ArrayQueue, LinkedQueue, CircularQueue, and PriorityQueue.
 package datastructure
 
 import (
diff --git a/datastructure/queue/circularqueue.go b/datastructure/queue/circularqueue.go
index 53f655e..b33ba55 100644
--- a/datastructure/queue/circularqueue.go
+++ b/datastructure/queue/circularqueue.go
@@ -1,3 +1,8 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure.
+// Queue structure contains ArrayQueue, LinkedQueue, CircularQueue, and PriorityQueue.
 package datastructure
 
 import (
diff --git a/datastructure/queue/linkedqueue.go b/datastructure/queue/linkedqueue.go
index 8e4f90d..d44cfd7 100644
--- a/datastructure/queue/linkedqueue.go
+++ b/datastructure/queue/linkedqueue.go
@@ -1,3 +1,8 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure.
+// Queue structure contains ArrayQueue, LinkedQueue, CircularQueue, and PriorityQueue.
 package datastructure
 
 import (
diff --git a/datastructure/queue/priorityqueue.go b/datastructure/queue/priorityqueue.go
index 9875486..741ec9a 100644
--- a/datastructure/queue/priorityqueue.go
+++ b/datastructure/queue/priorityqueue.go
@@ -1,3 +1,8 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure.
+// Queue structure contains ArrayQueue, LinkedQueue, CircularQueue, and PriorityQueue.
 package datastructure
 
 import (
diff --git a/datastructure/set/set.go b/datastructure/set/set.go
index 60326dd..186d905 100644
--- a/datastructure/set/set.go
+++ b/datastructure/set/set.go
@@ -1,6 +1,10 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. Set is a data container, like slice, but element of set is not duplicate.
 package datastructure
 
-// Set is a data container, like slice, but element of set is not duplicate
+// Set is a data container, like slice, but element of set is not duplicate.
 type Set[T comparable] map[T]struct{}
 
 // NewSet return a instance of set
diff --git a/datastructure/stack/arraystack.go b/datastructure/stack/arraystack.go
index 3b546fd..b0cbe88 100644
--- a/datastructure/stack/arraystack.go
+++ b/datastructure/stack/arraystack.go
@@ -1,3 +1,7 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. Stack structure contains ArrayStack and LinkedStack.
 package datastructure
 
 import "errors"
diff --git a/datastructure/stack/linkedstack.go b/datastructure/stack/linkedstack.go
index fb57a4c..af17846 100644
--- a/datastructure/stack/linkedstack.go
+++ b/datastructure/stack/linkedstack.go
@@ -1,3 +1,7 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. Stack structure contains ArrayStack and LinkedStack.
 package datastructure
 
 import (
diff --git a/datastructure/tree/bstree.go b/datastructure/tree/bstree.go
index 2a3fa41..db9618b 100644
--- a/datastructure/tree/bstree.go
+++ b/datastructure/tree/bstree.go
@@ -1,3 +1,7 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package datastructure contains some data structure. BSTree is binary search tree.
 package datastructure
 
 import (