Remove duplicates from a linked list.

ListNode.java

package com.interviewbytes.linkedlists;

public class ListNode {
    int val;
    ListNode next;

    ListNode(int x) {
        val = x;
    }
}

RemoveDuplicates.java

package com.interviewbytes.linkedlists;

public class RemoveDuplicates {

    public ListNode deleteDuplicates(ListNode head) {

        if (head == null) return null;

        ListNode current = head;

        ListNode sentinel = new ListNode(0);
        sentinel.next = current;

        head = head.next;

        while (head != null) {
            if (head.val != current.val) {
                current.next = head;
                current = current.next;
            }
            head = head.next;
        }

        current.next = null;

        return sentinel.next;

    }
}