82.Remove-Duplicates-from-Sorted-List-II

82. Remove Duplicates from Sorted List II

题目地址

题目描述

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

代码

Approach #1 Two while-loop

public class Solution {
public ListNode deleteDuplicates(ListNode head){
if (head == null) return null;
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode node = dummy;
while (node.next != null && node.next.next != null) {
if (node.next.val == node.next.next.val) {
int val_prev = node.next.val;
while (node.next != null && node.next.val == val_prev) {
node.next = node.next.next;
}
} else {
node = node.next;
}
}
return dummy.next;
}
}