# 82.remove-duplicates-from-sorted-list-ii

## Statement ``````输入：head = [1,2,3,3,4,4,5]

`````` ``````输入：head = [1,1,1,2,3]

``````

• 链表中节点数目在范围 `[0, 300]`
• `-100 <= Node.val <= 100`
• 题目数据保证链表已经按升序 排列

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

``````# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
def deleteDuplicates(self, head: ListNode) -> ListNode:
pre = 1000
cnt = 1
res = ListNode()
cur = res
cnt += 1
else:
if cnt == 1 and pre != 1000:
cur.next = ListNode()
cur = cur.next
cur.val = pre
cnt = 1