程式碼：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        while(head != NULL&&head->val == val) head = head->next;
        if(head == NULL) return head;
        ListNode* l = head;
        while(l->next != NULL) {
            if(l->next->val == val) 
                l->next = l->next->next;
            else
                l = l->next;
        }
        return head;
    }
};