203移除链表元素.c

struct ListNode* removeElements(struct ListNode* head, int val){
    struct ListNode ret, *p, *q;
    ret.next = head;
    p = &ret;
    while (p && p->next) {
        if (p->next->val == val) {
            q = p->next;
            p->next = q->next;
            free(q);
        } else {
            p = p->next;
        }
    }
    return ret.next;
    
}