2019-11-02 12:07:41 +08:00
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# 28. 对称的二叉树
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[NowCoder](https://www.nowcoder.com/practice/ff05d44dfdb04e1d83bdbdab320efbcb?tpId=13&tqId=11211&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
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## 题目描述
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2019-12-06 10:11:23 +08:00
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<div align="center"> <img src="https://cs-notes-1256109796.cos.ap-guangzhou.myqcloud.com/0c12221f-729e-4c22-b0ba-0dfc909f8adf.jpg" width="300"/> </div><br>
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2019-11-02 12:07:41 +08:00
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## 解题思路
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```java
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boolean isSymmetrical(TreeNode pRoot) {
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if (pRoot == null)
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return true;
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return isSymmetrical(pRoot.left, pRoot.right);
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}
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boolean isSymmetrical(TreeNode t1, TreeNode t2) {
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if (t1 == null && t2 == null)
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return true;
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if (t1 == null || t2 == null)
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return false;
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if (t1.val != t2.val)
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return false;
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return isSymmetrical(t1.left, t2.right) && isSymmetrical(t1.right, t2.left);
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}
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```
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