链表反转

 1 /* reverse singly linked list by adding each node after head from
 2  * node 2 to node N; then add head after the last node.
 3  */
 4 #include "init_list.h"
 5 
 6 ListNode *reverseList(ListNode *head) {
 7     ListNode *p = head->next, *q;
 8     while(NULL != p->next) {
 9         q = p->next;
10         p->next = q->next;
11         q->next = head->next;
12         head->next = q;
13     }
14     p->next = head;
15     head = p->next->next;
16     p->next->next = NULL;
17     return head;
18 }
19 
20 ListNode *reverse2List(ListNode *head) {
21     ListNode *p, *q, *r;
22     if (NULL == head || NULL == head->next) {
23         return head;
24     }
25     p = head;
26     q = head->next;
27     head->next = NULL;
28     while (q) {
29         r = q->next;
30         q->next = p;
31         p = q;
32         q = r;
33     }
34     return p; /* head = p */
35 }
36 
37 void reverse3List(ListNode *head) {
38     if (NULL == head || NULL == head->next) {
39         return head;
40     }
41     else {
42         ListNode* newhead = reverse3List(head->next);
43         head->next->next = head;
44         head->next = NULL;
45         return newhead;
46     }
47 }
48 int main()
49 {
50     ListNode *head = createList();
51     ListNode *newlist = reverse3List(head);
52     cout << "reversed list is : " << endl;
53     printList(newlist);
54     return 0;
55 }

#include <iostream>
using namespace std;

struct ListNode {
    int val;
    ListNode *next;
    ListNode(int x) : val(x), next(NULL) {}
};

ListNode *createList();
void printList (ListNode *phead);
ListNode *insertionSortList(ListNode *head);

 1 /*
 2  * init_list.cpp -- created to make some initiation of singly-linked list.
 3  * including struct ListNode{}
 4  * LN *createList(), void printList(*head),LN *insertionSortList(*head);
 5  * author -- zhy
 6  * date -- 2016-12-12
 7  */
 8 
 9 #include <iostream>
10 #include "cstdlib"
11 using namespace std;
12 
13 /**
14  * Definition for singly-linked list.
15   */
16 struct ListNode {
17     int val;
18     ListNode *next;
19     ListNode(int x) : val(x), next(NULL) {}
20 };
21 
22 
23 ListNode *createList () {
24     int i = 0, n;
25     cout << "Please input the length N of your list: ";
26     cin >> n;
27     cout << "now input n values of your list: " << endl;
28     ListNode *list = new ListNode(0);
29     ListNode *head = list;
30     for(; i < n; ++i)
31     {
32         head->next = new ListNode(0);
33         head = head->next;
34         cin >> head->val;
35     }
36     head = list->next;
37     return head;
38 }
39 
40 void printList (ListNode *phead) {
41     while (NULL != phead){
42         cout << phead->val << ‘ ‘;
43         phead = phead->next;
44     }
45     cout << endl;
46 }
47 
48 ListNode *insertionSortList(ListNode *head) {
49     if (!head || !head->next)
50        return head;
51     ListNode *dummy = new ListNode(-1);
52     ListNode *cur = head, *pre = dummy;
53     while (NULL != cur) {
54         pre = dummy;
55         while (NULL != pre->next && pre->next->val < cur->val) {
56             pre = pre->next;    //find suitable position to insert
57         }
58         ListNode *temp = new ListNode(cur->val);
59         temp->next = pre->next;
60         pre->next = temp;
61         
62         cur = cur->next;
63         //pre = dummy;
64     }
65     return dummy->next;
66 }