bool compare_lists(SinglyLinkedListNode* head1, SinglyLinkedListNode* head2) {
    while(head1 && head2 && head1->data == head2->data){
        head1 = head1->next;
        head2 = head2->next;
    }
    if(head1 || head2){
        return false;
    }
    return true;
}