bool isSametree(struct TreeNode*root1,struct TreeNode*root2)
{
if(root1==NULL&&root2==NULL)
return true;
if(root1==NULL||root2==NULL)
return false;
if(root1->val!=root2->val)
return false;
return isSametree(root1->left,root2->right)
&&isSametree(root1->right,root2->left);
}
bool isSymmetric(struct TreeNode* root) {
return isSametree(root->left,root->right);
}