LeetCode 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

按照常规，设定一个dummyHead元素来避免特殊情况的处理

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
 // 9:33
class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        ListNode dummyHead(0);
        dummyHead.next = head;
        ListNode* pre = &dummyHead;
        ListNode* cur = dummyHead.next;
        
        while (cur != NULL) {
            if (cur->val == val) {
                ListNode* del = cur;
                cur = cur->next;
                pre->next = cur;
                delete del;
            } else {
                pre = cur;
                cur = cur->next;
            }
        }
        return dummyHead.next;
    }
};