/*
 * @lc app=leetcode id=101 lang=cpp
 *
 * [101] Symmetric Tree
 */
/**
 * 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) {
         return isMirror(root, root);
    }
   
   


    bool isMirror(TreeNode* t1, TreeNode* t2) 
    {
        if (t1 == NULL && t2 == NULL) 
            return true;
        if (t1 == NULL || t2 == NULL) 
            return false;
        return (t1->val == t2->val) && isMirror(t1->right, t2->left) && isMirror(t1->left, t2->right);
    }

};