82. Remove Duplicates from Sorted List II

https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/

Python

class Solution:
    def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
        dummy = ListNode(val=None, next=head)
        pre, cur = dummy, head

        while cur:
            if cur.next and cur.val == cur.next.val:
                # Move over all duplicates
                while cur.next and cur.val == cur.next.val:
                    cur = cur.next
                pre.next = cur.next
            else:
                pre = pre.next

            cur = cur.next

        return dummy.next

Go

func deleteDuplicates(head *ListNode) *ListNode {
    dummy := new(ListNode)
    dummy.Next = head

    pre, cur := dummy, head

    for cur != nil {
        if cur.Next != nil && cur.Val == cur.Next.Val {
            for cur.Next != nil && cur.Val == cur.Next.Val {
                cur = cur.Next
            }
            pre.Next = cur.Next
        } else {
            pre = pre.Next
        }
        cur = cur.Next
    }

    return dummy.Next
}