diff --git a/codes/go/chapter_tree/binary_search_tree.go b/codes/go/chapter_tree/binary_search_tree.go
index 26eb94d..ac14e79 100644
--- a/codes/go/chapter_tree/binary_search_tree.go
+++ b/codes/go/chapter_tree/binary_search_tree.go
@@ -5,8 +5,9 @@
 package chapter_tree
 
 import (
-	. "github.com/krahets/hello-algo/pkg"
 	"sort"
+
+	. "github.com/krahets/hello-algo/pkg"
 )
 
 type BinarySearchTree struct {
diff --git a/codes/go/chapter_tree/binary_tree_bfs.go b/codes/go/chapter_tree/binary_tree_bfs.go
index d04102f..5c07a96 100644
--- a/codes/go/chapter_tree/binary_tree_bfs.go
+++ b/codes/go/chapter_tree/binary_tree_bfs.go
@@ -6,6 +6,7 @@ package chapter_tree
 
 import (
 	"container/list"
+
 	. "github.com/krahets/hello-algo/pkg"
 )
 
diff --git a/codes/go/chapter_tree/binary_tree_test.go b/codes/go/chapter_tree/binary_tree_test.go
index 2c05076..03a8553 100644
--- a/codes/go/chapter_tree/binary_tree_test.go
+++ b/codes/go/chapter_tree/binary_tree_test.go
@@ -5,8 +5,9 @@
 package chapter_tree
 
 import (
-	. "github.com/krahets/hello-algo/pkg"
 	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
 )
 
 func TestBinaryTree(t *testing.T) {