83. Remove Duplicates from Sorted List.py

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

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.

"""


# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
    def deleteDuplicates(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if not head:
            return head

        tail = head

        while tail.next:
            current = tail.next

            if current.val == tail.val:
                tail.next = current.next
            else:
                tail = current

        return head