#!/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: Implement an algorithm to determine if a string has all unique characters.
# 
# * [Constraints](#Constraints)
# * [Test Cases](#Test-Cases)
# * [Algorithm](#Algorithm)
# * [Code](#Code)
# * [Unit Test](#Unit-Test)
# * [Solution Notebook](#Solution-Notebook)

# ## Constraints
# 
# * Can we assume the string is ASCII?
#     * Yes
#     * Note: Unicode strings could require special handling depending on your language
# * Can we assume this is case sensitive?
#     * Yes
# * Can we use additional data structures?
#     * Yes
# * Can we assume this fits in memory?
#     * Yes

# ## Test Cases
# 
# * None -> False
# * '' -> True
# * 'foo' -> False
# * 'bar' -> True

# ## Algorithm
# 
# Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/unique_chars/unique_chars_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[ ]:


class UniqueChars(object):

    def has_unique_chars(self, string):
        # TODO: Implement me
        pass


# ## Unit Test

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

# In[ ]:


# %load test_unique_chars.py
import unittest


class TestUniqueChars(unittest.TestCase):

    def test_unique_chars(self, func):
        self.assertEqual(func(None), False)
        self.assertEqual(func(''), True)
        self.assertEqual(func('foo'), False)
        self.assertEqual(func('bar'), True)
        print('Success: test_unique_chars')


def main():
    test = TestUniqueChars()
    unique_chars = UniqueChars()
    test.test_unique_chars(unique_chars.has_unique_chars)
    try:
        unique_chars_set = UniqueCharsSet()
        test.test_unique_chars(unique_chars_set.has_unique_chars)
        unique_chars_in_place = UniqueCharsInPlace()
        test.test_unique_chars(unique_chars_in_place.has_unique_chars)
    except NameError:
        # Alternate solutions are only defined
        # in the solutions file
        pass


if __name__ == '__main__':
    main()


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