remove_linked_list_element.cpp

/**
 * 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) {}
 * };
 */
static const int __ = []() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(NULL);
  std::cout.tie(NULL);
  return 0;
}();

class Solution {
public:
  ListNode *removeElements(ListNode *head, int val) {
    if (head == NULL) {
      return head;
    }
    while (head != NULL && head->val == val) {
      head = head->next;
      // temp = temp->next;
    }
    ListNode *temp = head;
    while (temp != NULL && temp->next != NULL) {
      if (temp->next->val == val) {
        temp->next = temp->next->next;
      } else {
        temp = temp->next;
      }
    }
    return head;
  }
};