剑指Offer(3)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) {
stack<ListNode*> reverse;//定义一个栈
vector<int> result;
if(head==nullptr)
return result;
while(head!=nullptr)//入栈
{
reverse.push(head);
head=head->next;
}
while(!reverse.empty())//如果栈不为空
{
//把栈中元素存到数组中
result.push_back(reverse.top()->val);
reverse.pop();
}
return result;
}
};