remove-duplicates-from-sorted-list.py

# 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.
#
#  
# Example 1:
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# Input: head = [1,1,2]
# Output: [1,2]
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# Example 2:
#
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# Input: head = [1,1,2,3,3]
# Output: [1,2,3]
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#
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# Constraints:
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# 	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.
#
#


# 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]:
        current = head
        while current != None and current.next != None:
            if current.val == current.next.val:
                current.next = current.next.next
            else:
                current = current.next
        return head