递归 vector 打印

class Solution {
public:
    vector<int> printListReversingly(ListNode* head) {
        vector<int> vi;
        if(head == NULL) 
            return vi;
        else
        {
            vi =printListReversingly(head->next);
            vi.push_back(head->val);
            return vi;
        }

    }
};