203. Remove Linked List Elements

 1 /**
 2  * Definition for singly-linked list.
 3  * struct ListNode {
 4  *     int val;
 5  *     ListNode *next;
 6  *     ListNode(int x) : val(x), next(NULL) {}
 7  * };
 8  */
 9 static int wing=[]()
10 {
11     std::ios::sync_with_stdio(false);
12     cin.tie(NULL);
13     return 0;
14 }();
15 
16 class Solution 
17 {
18 public:
19     ListNode* removeElements(ListNode* head, int val) 
20     {
21         if(head==NULL)
22             return NULL;
23         ListNode *pre=new ListNode(0);
24         pre->next=head;
25         ListNode *fon=head;
26         while(fon!=NULL)
27         {
28             if(fon->val!=val)
29             {
30                 pre->next->val=fon->val;
31                 pre=pre->next;
32             }
33             fon=fon->next;
34         }
35         pre->next=NULL;
36         return (head->val==val)? NULL:head;
37     }
38 };