【LeetCode】Symmetric Tree

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