diff --git a/notes/55.2 平衡二叉树.md b/notes/55.2 平衡二叉树.md
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@@ -6,7 +6,7 @@
平衡二叉树左右子树高度差不超过 1。
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+
## 解题思路
diff --git a/notes/pics/offer-balanced-tree.png b/notes/pics/offer-balanced-tree.png
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