题解 | #从尾到头打印链表#

/**
*  struct ListNode {
*        int val;
*        struct ListNode *next;
*        ListNode(int x) :
*              val(x), next(NULL) {
*        }
*  };
*/
class Solution {
public:
    vector<int> printListFromTailToHead(ListNode* head) {
        vector<int>ans;
        backtrack(head, ans);
        return ans;
        
    }

    void backtrack(ListNode* head,vector<int>&ans){
        if(head!=nullptr){
            backtrack(head->next, ans);//逆序返回
            ans.push_back(head->val);
        }

    }
};