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.
Examples
Input: head = [1,2,3,3,4,4,5] Output: [1,2,5]
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.\
Java Solution
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode deleteDuplicates(ListNode head) {
if (head == null || head.next == null) {
return head;
}
ListNode result = new ListNode(0, head);
ListNode pre = result;
while(head != null && head.next != null) {
if(head.val == head.next.val) {
while(head.next != null && head.val == head.next.val) {
head = head.next;
}
head = head.next;
pre.next = head;
} else {
head = head.next;
pre = pre.next;
}
}
return result.next;
}
}
