链表——从尾到头遍历（链表反转）

/**
*  struct ListNode {
*        int val;
*        struct ListNode *next;
*        ListNode(int x) :
*              val(x), next(NULL) {
*        }
*  };
*/
class Solution {
public:
    vector<int> printListFromTailToHead(ListNode* head) {
        //vector<int> ret;
        /*if(!head)
        {
            return ret;
        }
        ret = printListFromTailToHead(head->next);
        return ret;*/
        /*while(head)
        {
            ret.push_back(head->val);
            head=head->next;
        }
        std::reverse(ret.begin(),ret.end());
        return ret;*/
        ListNode* pre =nullptr;
        ListNode* cur = head;
        ListNode* temp = cur;
        while(cur)
        {
            temp = cur->next;
            cur->next=pre;
            pre = cur;
            cur = temp;
        }

        vector<int > ret;
        while(pre)
        {
            ret.push_back(pre->val);
            pre = pre->next;
        }
        return ret;
    }
};

考虑用到三个指针，分别为，现在，前一个，后一个，再用一个temp暂存!