[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:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

/** * 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).