leetcode203. 移除链表元素

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* removeElements(struct ListNode* head, int val) {
    while(head && head->val == val)
    {
        struct ListNode* tmp = head;
        head = head->next;
        free(tmp);
    }
    if(head == NULL) return head;
    struct ListNode* cur = head;
    while(cur->next)
    {
        if(cur->next->val == val)
        {
            struct ListNode* tmp = cur->next;
            cur->next = cur->next->next;  
            free(tmp);
        }
        else
        {
            cur = cur->next;
        }
    }
    return head;
}