①reverse做法

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> printListReversingly(ListNode* head) {
        vector<int> res;
        for( auto p=head; p; p=p->next )
        {
                res.push_back(p->val);
        }
        reverse(res.begin(),res.end());
        return res;
    }
};

②递归做法

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