bool isSub(struct TreeNode* root, struct TreeNode* subRoot)
{
    if((root == NULL && subRoot != NULL)|| (subRoot == NULL && root != NULL))
    {
        return false;
    }
    if(root == NULL && subRoot == NULL)
    {
        return true;
    }
    if(root->val == subRoot->val)
    {
        return (isSub(root->left,subRoot->left) && isSub(root->right,subRoot->right));
    }
    else
    {
        return false;
    }
    return true;
}

 bool dfs(struct TreeNode* root, struct TreeNode* subRoot) {
        if (!root) {
            return false;
        }
        return isSub(root, subRoot) || dfs(root->left, subRoot) || dfs(root->right, subRoot);
    }

bool isSubtree(struct TreeNode* root, struct TreeNode* subRoot){
    
    return dfs(root,subRoot);
}