#!/usr/bin/env python
# coding: utf-8

# This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).

# # Challenge Notebook

# ## Problem: Remove duplicates from a linked list.
# 
# * [Constraints](#Constraints)
# * [Test Cases](#Test-Cases)
# * [Algorithm](#Algorithm)
# * [Code](#Code)
# * [Unit Test](#Unit-Test)
# * [Solution Notebook](#Solution-Notebook)

# ## Constraints
# 
# * Can we assume this is a non-circular, singly linked list?
#     * Yes
# * Can you insert None values in the list?
#     * No
# * Can we assume we already have a linked list class that can be used for this problem?
#     * Yes
# * Can we use additional data structures?
#     * Implement both solutions
# * Can we assume this fits in memory?
#     * Yes

# ## Test Cases
# 
# * Empty linked list -> []
# * One element linked list -> [element]
# * General case with no duplicates
# * General case with duplicates

# ## Algorithm
# 
# Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/linked_lists/remove_duplicates/remove_duplicates_solution.ipynb).  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.

# ## Code

# In[ ]:


get_ipython().run_line_magic('run', '../linked_list/linked_list.py')
get_ipython().run_line_magic('load', '../linked_list/linked_list.py')


# In[ ]:


class MyLinkedList(LinkedList):

    def remove_dupes(self):
        # TODO: Implement me
        pass


# ## Unit Test

# 
# 
# **The following unit test is expected to fail until you solve the challenge.**

# In[ ]:


# %load test_remove_duplicates.py
import unittest


class TestRemoveDupes(unittest.TestCase):

    def test_remove_dupes(self, linked_list):
        print('Test: Empty list')
        linked_list.remove_dupes()
        self.assertEqual(linked_list.get_all_data(), [])

        print('Test: One element list')
        linked_list.insert_to_front(2)
        linked_list.remove_dupes()
        self.assertEqual(linked_list.get_all_data(), [2])

        print('Test: General case, duplicates')
        linked_list.insert_to_front(1)
        linked_list.insert_to_front(1)
        linked_list.insert_to_front(3)
        linked_list.insert_to_front(2)
        linked_list.insert_to_front(3)
        linked_list.insert_to_front(1)
        linked_list.insert_to_front(1)
        linked_list.remove_dupes()
        self.assertEqual(linked_list.get_all_data(), [1, 3, 2])

        print('Test: General case, no duplicates')
        linked_list.remove_dupes()
        self.assertEqual(linked_list.get_all_data(), [1, 3, 2])

        print('Success: test_remove_dupes\n')


def main():
    test = TestRemoveDupes()
    linked_list = MyLinkedList(None)
    test.test_remove_dupes(linked_list)


if __name__ == '__main__':
    main()


# ## Solution Notebook
# 
# Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/linked_lists/remove_duplicates/remove_duplicates_solution.ipynb) for a discussion on algorithms and code solutions.