力扣203. 移除链表元素

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        ListNode* dummyhead = new ListNode();
        dummyhead->next = head;

        ListNode* cur = dummyhead;
        
        while(cur->next != nullptr) {
            if(cur->next->val == val) {
                ListNode* tmp = cur->next;
                cur->next = tmp->next;
                delete tmp;
            } else {
                cur = cur->next;
            }
        }

        ListNode* result = dummyhead->next;
        delete dummyhead;

        return result;
    }
};