[LeetCode] 83. Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
Thought process:
Iterate through the list, and check if the value of the next node is the same as this node. There are two cases:

  1. Value of the next node == value of this node: delete next node.
  2. Otherwise, increment current node.

Solution:
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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode current = head;
        
        while (current != null) {
            if (current.next != null && current.next.val == current.val) {
                current.next = current.next.next;
            } else {
                current = current.next;
            }
        }
        
        return head;
    }
}

Time complexity: O(n).
Location: San Jose, CA, USA

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