# 82. Remove Duplicates from Sorted List II

## 03 Jan 82. Remove Duplicates from Sorted List II

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.

Recursive

• Idea

• Base case: list is empty or contains only one element –> No duplicates
• Recursive case: Assuming that the rest of the list is already done removing duplicates, we only need to consider the first part
• There’s no duplicate in the first part
• There’re duplicates in the first part
•
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]: