Leetcode 单链表删除Remove Linked List Elements

Remove all elements from a linked list of integers that have value val.

Example

Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6

Return: 1 --> 2 --> 3 --> 4 --> 5

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     struct ListNode *next;
* };
*/
struct ListNode* removeElements(struct ListNode* head, int val) {
if(head==NULL)return head;
struct ListNode *p=NULL;
while(head&&val==head->val){p=head;head=head->next;free(p);}//头
p=head;
while(p&&p->next){;
if(val==p->next->val){struct ListNode *tepm=p->next;p->next=tepm->next;free(tepm);}
else p=p->next;}//内部或尾部
return head;
}