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

Solution: Using dummy node

There are three different situations:

• The target node might be the head
• The target node might be the tail
• The taregt node might be in the middle

In a situation like this, we can utilize the dummy head to simplify the deletion.

ListNode* removeElements(ListNode* head, int val) {
    ListNode *dummyHead = new ListNode(0);
    dummyHead->next = head;

    ListNode *cur = dummyHead;
    while (cur && cur->next) {
        if (cur->next->val == val) {
            cur->next = cur->next->next;
        } else {
            cur = cur->next;
        }
    }

    return dummyHead->next;
}