83. Remove Duplicates from Sorted List - LeetCode 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: Optional[ListNode]) -> Optional[ListNode]:
        ans = ListNode(-1000)
        ptr = ans
        
        while head:
            if ptr.val != head.val:
                ptr.next = ListNode(head.val)
                ptr = ptr.next
           
        
            head = head.next
        
        return ans.next