# [leetcode]Symmetric Tree

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

For example, this binary tree is symmetric:

```    1
/ \
2   2
/ \ / \
3  4 4  3
```

But the following is not:

```    1
/ \
2   2
\   \
3    3
```

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

```/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
bool isSymmetric(TreeNode* root) {
if(root == NULL){
return true;
}
return isSame(root->left, root->right);
}
bool isSame(TreeNode * a, TreeNode * b){
if(a == NULL && b == NULL){
return true;
}
else if(a == NULL || b == NULL){
return false;
}
else{
if(a->val != b->val){
return false;
}
else{
return isSame(a->left, b->left) && isSame(a->right, b->right);
}
}
}
};```

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