[LeetCode]Insertion Sort List

题目描述：

Sort a linked list using insertion sort.

解决方案:

该题目就是用插入排序来对链表进行排序，很简单，直接上代码。

 1 class Solution {
 2 public:
 3     ListNode *insertionSortList(ListNode *head) {
 4         ListNode *q = head;
 5         ListNode *temp = new ListNode(0);
 6         temp->val = INT_MIN;
 7         temp->next = NULL;
 8         ListNode *p = temp;
 9         ListNode * pre = NULL;
10         ListNode *k = NULL;
11         ListNode *f = NULL;
12         while (q != NULL) {
13             f = q;
14             q = q->next;
15             k = temp;
16             while(1) {
17                 if (k == NULL) {
18                     f->next = NULL;
19                     pre->next = f;
20                     break;
21                 }
22                 if (f->val < k->val) {
23                     f->next = pre->next;
24                     pre->next = f;
25                     pre = k;
26                     break;
27                 }
28                 pre = k;
29                 k = k->next;
30             }
31             pre = NULL; 
32         }
33         p = temp->next;
34         temp->next = NULL;
35         delete temp;
36         return p;
37     }
38 };