Remove Duplicates from Sorted List II.md

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Example 1:

Input: 1->2->3->3->4->4->5 Output: 1->2->5 Example 2:

Input: 1->1->1->2->3 Output: 2->3

My code:

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def deleteDuplicates(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if head==None:
            return head
        if head.next==None:
            return head
        origin_head=head
        count=0
        value=head.val
        pre_head=head
        now_head=head
        while head!=None and head.next!=None:
            if head.val==head.next.val:
                while head.next!=None and head.val==head.next.val:
                    head=head.next
                if head.val==origin_head.val:
                    origin_head=head.next
                    if origin_head==None:
                        return None
                pre_head.next=head.next
                head=head.next
                continue
            pre_head=head
            head=head.next
        
        return origin_head
              

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