ListNode* removeElements(ListNode* head, int val) {

ListNode dummy{0};

dummy.next = head;

auto *prev = &dummy, *cur = dummy.next;

while (cur) {

if (cur->val == val) {

prev->next = cur->next;

delete cur;

} else {

prev = cur;

}

cur = cur->next;

}

return dummy.next;

}

ListNode* removeElements(ListNode* head, int val) {

for (auto *indirect = &head; *indirect != nullptr; ) {

if ((*indirect)->val == val) {

*indirect = (*indirect)->next;

continue;

}

indirect = &((*indirect)->next) ;

}

return head;

}