203. Remove Linked List Elements Solution 1 (time O(n), space O(1)) /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; this.next = next; } * } */ class Solution { public ListNode removeElements(ListNode head, int val) { ListNode dummy = new ListNode(-1, head); ListNode p = dummy; while (p.next != null) { if (p.next.val == val) { p.next = p.next.next; } else { p = p.next; } } return dummy.next; } }