From a2f7147a9386ca8949cc4774c0ea6e57468119b3 Mon Sep 17 00:00:00 2001
From: Jerry-306 <82520819+Jerry-306@users.noreply.github.com>
Date: Sat, 25 Sep 2021 20:08:41 +0800
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选择从数组前头插入数值，避免最后反转数组的操作，减少计算时间
---
 problems/0102.二叉树的层序遍历.md | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/problems/0102.二叉树的层序遍历.md b/problems/0102.二叉树的层序遍历.md
index 5128d6ec..7c43a472 100644
--- a/problems/0102.二叉树的层序遍历.md
+++ b/problems/0102.二叉树的层序遍历.md
@@ -421,9 +421,10 @@ var levelOrderBottom = function(root) {
             node.left&&queue.push(node.left);
             node.right&&queue.push(node.right);
         }
-        res.push(curLevel);
+	// 从数组前头插入值，避免最后反转数组，减少运算时间
+        res.unshift(curLevel);
     }
-    return res.reverse();
+    return res;
 };
 ```