Java ListNode 遞歸 遍歷

ListNode 基本結構

　

class ListNode {
    int val;
    ListNode next;

    ListNode(int val) {
        this.val = val;
    }
}

遞歸遍歷到List

    private void pbulic(ArrayList<Integer> list,ListNode listNode) {
        if (listNode == null) {
            return;
        }
// 　　　　list.add(listNode.val);//從頭開始遍歷
        pbulic(list,listNode.next);
        list.add(listNode.val);//從尾部開始遍歷
    }

從頭遍歷 到List

ArrayList<Integer> list = new ArrayList<Integer>();
        ArrayList<Integer> listInv = new ArrayList<Integer>();

        ListNode now = listNode;
        while (now != null) {
            list.add(now.val);
            now = now.next;
        }

        for (int i = list.size() - 1; i > -1; i--) {
            listInv.add(list.get(i));
        }
        log.info(listInv);
        now = listNode;
        while (now != null) {
            log.info(now.val);
            now = now.next;
        }
        return listInv;