leetcode83. Remove Duplicates from Sorted List

Given the head of a sorted linked list, delete all duplicates such that each element appears only once. Return the linked list sorted as well.

Input: head = 1,1,2

Output: 1,2

Input: head = 1,1,2,3,3

Output: 1,2,3

给定一个已排序的链表的头 head ， 删除所有重复的元素，使每个元素只出现一次 。返回 已排序的链表 。

class Solution:
    def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
        if head is None:
            return None
        cur = head
        while cur.next:
            if cur.next.val == cur.val:
                cur.next = cur.next.next
            else:
                cur = cur.next
        return head