打印链表从尾到头（reverse（））
从尾到头打印链表
http://www.nowcoder.com/questionTerminal/d0267f7f55b3412ba93bd35cfa8e8035
class Solution {
public:
vector<int> printListFromTailToHead(ListNode* head) {
vector<int> res;
while(head)res.push_back(head->val),head=head->next;
reverse(res.begin(),res.end());
return res;
}
};
