bool isSym(struct TreeNode* p,struct TreeNode* q)
{
    if (!p && !q)
     return true;
    if (!p || !q) 
    return false;
   if(p->val != q->val)
   return false;
    else
    return  p->val == q->val &&isSym(p->left,q->left)&& isSym(p->right,q->right);
}

bool isSameTree(struct TreeNode* p, struct TreeNode* q){
    return isSym(p,q);
}