递归或者翻转，递归空间换时间

/**
*  struct ListNode {
*        int val;
*        struct ListNode *next;
*        ListNode(int x) :
*              val(x), next(NULL) {
*        }
*  };
*/
class Solution {
  public:
    vector<int> printListFromTailToHead(ListNode* head) {
      std::vector<int> res;
      
      recursion(head, res);
      
      return res;
    }
  private:
    void recursion(ListNode *head, std::vector<int> &res) {
      if (head == nullptr) {
        return ;
      }
      
      recursion(head->next, res);
      res.push_back(head->val);
    }
};