diff --git a/priority_queue/vbt.go b/priority_queue/vbt.go
index 6ed7209..78179d9 100644
--- a/priority_queue/vbt.go
+++ b/priority_queue/vbt.go
@@ -451,9 +451,9 @@ func (tree *vbTree) Put(key interface{}) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				cur = tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -861,9 +861,9 @@ func (tree *vbTree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				cur = tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/priority_queuekey/vbtkey.go b/priority_queuekey/vbtkey.go
index faf4217..292f4f5 100644
--- a/priority_queuekey/vbtkey.go
+++ b/priority_queuekey/vbtkey.go
@@ -451,9 +451,9 @@ func (tree *vbTree) Put(key, value interface{}) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				cur = tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -861,9 +861,9 @@ func (tree *vbTree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				cur = tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/lsv/dtree.go b/tree/lsv/dtree.go
index 35540a4..92e855a 100644
--- a/tree/lsv/dtree.go
+++ b/tree/lsv/dtree.go
@@ -513,9 +513,9 @@ func (tree *DTree) Put(key, value []rune) (isInsert bool) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.family[1].size, cur.family[2].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -970,9 +970,9 @@ func (tree *DTree) fixSizeWithRemove(cur *DNode) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/lsv/itree.go b/tree/lsv/itree.go
index d0825a4..d544ae3 100644
--- a/tree/lsv/itree.go
+++ b/tree/lsv/itree.go
@@ -41,9 +41,9 @@ func (tree *ITree) Put(key, value []rune) (isInsert bool) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.family[1].size, cur.family[2].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.ifixSize(cur, ls, rs)
 			}
 		}
@@ -433,9 +433,9 @@ func (tree *ITree) ifixSizeWithRemove(cur *INode) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := igetChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.ifixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/vbt/vbt.go b/tree/vbt/vbt.go
index df80f91..0beec47 100644
--- a/tree/vbt/vbt.go
+++ b/tree/vbt/vbt.go
@@ -443,9 +443,9 @@ func (tree *Tree) Put(key interface{}) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -874,9 +874,9 @@ func (tree *Tree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/vbtdup/vbtdup.go b/tree/vbtdup/vbtdup.go
index fa7fe6a..469a35b 100644
--- a/tree/vbtdup/vbtdup.go
+++ b/tree/vbtdup/vbtdup.go
@@ -445,9 +445,9 @@ func (tree *Tree) Put(value interface{}) (isInsert bool) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -895,9 +895,9 @@ func (tree *Tree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/vbtkey/vbtkey.go b/tree/vbtkey/vbtkey.go
index d319995..f545760 100644
--- a/tree/vbtkey/vbtkey.go
+++ b/tree/vbtkey/vbtkey.go
@@ -446,9 +446,9 @@ func (tree *Tree) Put(key, value interface{}) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -884,9 +884,9 @@ func (tree *Tree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {
diff --git a/tree/vbtkeydup/vbtdupkey.go b/tree/vbtkeydup/vbtdupkey.go
index 51cfbd8..7e3da43 100644
--- a/tree/vbtkeydup/vbtdupkey.go
+++ b/tree/vbtkeydup/vbtdupkey.go
@@ -446,9 +446,9 @@ func (tree *Tree) Put(key, value interface{}) (isInsert bool) {
 	for cur := tree.root; ; {
 
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := cur.children[0].size, cur.children[1].size
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		}
@@ -896,9 +896,9 @@ func (tree *Tree) fixSizeWithRemove(cur *Node) {
 	for cur != nil {
 		cur.size--
 		if cur.size > 8 {
-			factor := cur.size / 10 // or factor = 1
+			factor := cur.size >> 3 // or factor = 1
 			ls, rs := getChildrenSize(cur)
-			if rs >= ls*2+factor || ls >= rs*2+factor {
+			if rs >= (ls<<1)+factor || ls >= (rs<<1)+factor {
 				tree.fixSize(cur, ls, rs)
 			}
 		} else if cur.size == 3 {