// prev = NULL, pt = NULL
void fixSwapNode(Node* curr, Node* prev, Node* pt1, Node* pt2, Node* pt){
    if(pt == NULL)
        pt = curr;
    if(curr){
        fixSwapNode(curr->left, prev, pt1, pt2, pt);
        if(prev){
            if(pt1 == NULL && pt2 == NULL && prev->data > curr->data){
                pt1 = prev;
                pt2 = curr;
            }else if(pt1 != NULL && pt2 != NULL && prev->data > curr->data){
                pt2 = curr;
            }
        }
        fixSwapNode(curr->right, curr, pt1, pt2, pt);
    }
    if(pt == curr){
        int tmp = pt1->data;
        pt1->data = pt2->data;
        pt2->data = tmp;
    }
}