[LC] 83. Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

Example 1:

Input: 1->1->2
Output: 1->2

Example 2:

Input: 1->1->2->3->3
Output: 1->2->3

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if (head == null || head.next == null) {
            return head;
        }
        ListNode cur = head;
        while (cur.next != null) {
            if (cur.val == cur.next.val) {
                // delete the next node
                cur.next = cur.next.next;
            } else {
                // move forward
                cur = cur.next;
            }
        }
        return head;
    }
}