Solution

• 迭代法

/**
*  struct ListNode {
*        int val;
*        struct ListNode *next;
*        ListNode(int x) :
*              val(x), next(NULL) {
*        }
*  };
*/
class Solution {
public:
    vector<int> printListFromTailToHead(ListNode* head) {
        vector<int> array;
        ListNode* cur = head;
        while (cur) {
            // 头插法
            array.insert(array.begin(), cur->val);
            cur = cur->next;
        }
        return array;
    }
};

• 递归法

class Solution {
public:
    vector<int> printListFromTailToHead(ListNode* head) {
        res.clear();
        travel(head);
        return res;
    }
private:
    vector<int> res;
    void travel(ListNode* head) {
        if (head == nullptr) return;
        travel(head->next);
        res.push_back(head->val);
    }
};