Leet Code OJ 101. Symmetric Tree [Difficulty: Easy]

题目：
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).

For example, this binary tree is symmetric:

But the following is not:

Note:
Bonus points if you could solve it both recursively and iteratively.

翻译：
给定一个二叉树，检测它是不是一个它自己的镜像（左右对称）。

代码：

/*** Definition for a binary tree node.* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode(int x) { val = x; }* }*/
public class Solution {public boolean isSymmetric(TreeNode root) {if(root==null){return true;}else{return isSame(root.left,root.right);}}public boolean isSame(TreeNode left,TreeNode right) {if(left==null&&right==null){return true;}else if(left!=null&&right!=null){if(left.val!=right.val){return false;}boolean res1=isSame(left.left,right.right);boolean res2=isSame(left.right,right.left);if(res1&&res2){return true;}else{return false;}}else{return false;}}
}

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