public boolean checkNaive(List<Integer> list) {
        for (int idx = 0; idx < list.size(); ++idx)
            if (idx != list.get(idx)) {
                System.out.print("[FAILED] ");
                printList(list);
                return false;
            }

        System.out.print("[PASSED] ");
        printList(list);
        return true;
    }