LeetCode Top Interview 150
82. Remove Duplicates from Sorted List II
Medium
Given the head of 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: head = [1,2,3,3,4,4,5]
Output: [1,2,5]
Example 2:
Input: head = [1,1,1,2,3]
Output: [2,3]
Constraints:
- The number of nodes in the list is in the range
[0, 300]. -100 <= Node.val <= 100- The list is guaranteed to be sorted in ascending order.
Solution
using LeetCodeNet.Com_github_leetcode;
/**
* Definition for singly-linked list.
* public class ListNode {
* public int val;
* public ListNode next;
* public ListNode(int val=0, ListNode next=null) {
* this.val = val;
* this.next = next;
* }
* }
*/
public class Solution {
public ListNode DeleteDuplicates(ListNode head) {
ListNode dummy = new ListNode(0, head);
ListNode prev = dummy;
while (head != null) {
if (head.next != null && head.val == head.next.val) {
while (head.next != null && head.val == head.next.val) {
head = head.next;
}
prev.next = head.next;
} else {
prev = prev.next;
}
head = head.next;
}
return dummy.next;
}
}