82. Remove Duplicates from Sorted List II

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LeetCode

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Problem

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Example 1:

Input: 1->2->3->3->4->4->5
Output: 1->2->5

Example 2:

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

Code

/**
 * 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 dummy = new ListNode(-1);
        dummy.next = head;
        ListNode curr = dummy;

        while(curr.next != null && curr.next.next != null){
            if(curr.next.val == curr.next.next.val){
                int val = curr.next.val;
                while(curr.next != null && curr.next.val == val){
                    curr.next = curr.next.next;
                }
            } else {
                curr = curr.next;
            }
        }

        return dummy.next;
    }
}