反转链表

输入一个链表，从尾到头打印链表每个节点的值。

 1 #include <iostream>
 2 #include <vector>
 3 #include <stack>
 4 
 5 using namespace std;
 6 
 7 struct ListNode{
 8     ListNode(int x) : val(x), next(NULL) {}
 9     int val;
10     struct ListNode* next;
11 };
12 
13 class Solution {
14 public:
15     vector<int> printListFromTailToHead(ListNode* head)
16     {
17         vector<int> vec ;
18         stack<int> sta;
19         ListNode* p = head;
20         while (p != NULL){
21             sta.push(p->val);
22             p = p->next;
23         }
24         int length = sta.size();
25         for (int i = 0; i < length; ++i){
26             vec.push_back(sta.top());
27             sta.pop();
28         }
29         return vec;
30     }
31 
32     void createList(ListNode* pHead, vector<int>& vec)
33     {
34         ListNode* p = pHead;
35         vector<int>::iterator iter = vec.begin();
36         for (; iter != vec.end(); ++iter)
37         {
38             ListNode* pNewNode = new ListNode(*iter);
39             p->next = pNewNode;
40             p = pNewNode;
41         }
42     }
43 
44 };
45 
46 int main()
47 {
48     int number;
49     cout << "Please input number:";
50     cin >> number;
51     vector<int> vec ;
52     cout << "Please input node val:";
53     for (int i = 0; i < number; ++i)
54     {
55         int nodeVal;
56         cin >> nodeVal;
57         vec.push_back(nodeVal);
58     }
59 
60     ListNode* head = new ListNode(0);
61     Solution* pSolution = new Solution();
62     pSolution->createList(head, vec);
63     vector<int> result ;
64     result = pSolution->printListFromTailToHead(head);
65     for (auto& i : result)
66     {
67         cout << i << endl;
68     }
69     system("pause");
70     return 0;
71 }

方法一：链表从尾到头输出，利用递归实现，不使用库函数直接printf输出的时候用递归比较好

 1 链接：https://www.nowcoder.com/questionTerminal/d0267f7f55b3412ba93bd35cfa8e8035
 2 来源：牛客网
 3 
 4 /**
 5 *  struct ListNode {
 6 *        int val;
 7 *        struct ListNode *next;
 8 *        ListNode(int x) :
 9 *              val(x), next(NULL) {
10 *        }
11 *  };
12 */
13 class Solution {
14 public:
15     vector<int> printListFromTailToHead(struct ListNode* head) {
16         vector<int> value;
17         if(head != NULL)
18         {
19             value.insert(value.begin(),head->val);
20             if(head->next != NULL)
21             {
22                 vector<int> tempVec = printListFromTailToHead(head->next);
23                 if(tempVec.size()>0)
24                 value.insert(value.begin(),tempVec.begin(),tempVec.end());  
25             }         
26              
27         }
28         return value;
29     }
30 };

 

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posted @ 2017-11-14 20:11  dangeal  阅读(181)  评论(0)  编辑  收藏  举报