从尾到头打印链表

class Solution {
public:
    vector<int> printListFromTailToHead(ListNode* head) {
        vector<int> res;
        vector<int> stack;
        while(head)
        {
            stack.push_back(head->val);
            head=head->next;
        }
        for(int idx=stack.size()-1; idx>=0; --idx)
        {
            res.push_back(stack[idx]);
        }
        return res;
    }
};