day 23, more linked lists.py

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None


class Solution:
    def insert(self, head, data):
        p = Node(data)
        if not head:
            head = p
        elif not head.next:
            head.next = p
        else:
            start = head
            while (not start.next):
                start = start.next
            start.next = p
        return head

    def display(self, head):
        current = head
        while current:
            print(current.data, end=' ')
            current = current.next

    def remove_duplicates(self, head):
        # Write your code here
        previous = head
        s = set()
        s.add(previous.data)
        current = previous.next
        while current:
            if current.data in s:
                previous.next = current.next
            else:
                s.add(current.data)
                previous = current
            current = current.next
        return head


mylist = Solution()
T = int(input())
head = None
for i in range(T):
    data = int(input())
    head = mylist.insert(head, data)
head = mylist.remove_duplicates(head)
mylist.display(head)