diff --git a/avl/avl.go b/avl/avl.go
index 0455b4c..eed5d80 100644
--- a/avl/avl.go
+++ b/avl/avl.go
@@ -153,7 +153,9 @@ func (tree *Tree) GetRange(k1, k2 interface{}) (result []interface{}) {
 
 		result = make([]interface{}, 0, 16)
 
-		iter := NewIterator(min)
+		// iter := NewIterator(min)
+		tree.iter.SetNode(min)
+		iter := tree.iter
 		for iter.Next() {
 			result = append(result, iter.Value())
 			if iter.cur == max {
@@ -228,7 +230,9 @@ func (tree *Tree) getArountNode(key interface{}) (result [3]*Node) {
 			n = n.children[1]
 			lastc = c
 		case 0:
-			iter := NewIterator(n)
+			// iter := NewIterator(n)
+			tree.iter.SetNode(n)
+			iter := tree.iter
 			iter.Prev()
 			for iter.Prev() {
 				if tree.Compare(iter.cur.value, n.value) == 0 {
diff --git a/lastack/lastack_test.go b/lastack/lastack_test.go
index 1281f1d..992ad81 100644
--- a/lastack/lastack_test.go
+++ b/lastack/lastack_test.go
@@ -25,16 +25,19 @@ func TestPush(t *testing.T) {
 		t.Error(s.String(), " size ", s.size)
 	}
 
+	var l []int
+
 	for i := 0; i < 10; i++ {
 		v := randomdata.Number(0, 10)
 		s.Push(v)
+		l = append(l, v)
 	}
 
 	for i := -1; i < 11; i++ {
 		v, ok := s.Get(i)
 		t.Error(v, ok)
 	}
-
+	t.Error(l)
 }
 
 func BenchmarkGet(b *testing.B) {