diff --git a/arrays_strings/non_repeated/__init__.py b/arrays_strings/non_repeated/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/arrays_strings/non_repeated/non_repeat_challenge.ipynb b/arrays_strings/non_repeated/non_repeat_challenge.ipynb new file mode 100644 index 0000000..0d2ed67 --- /dev/null +++ b/arrays_strings/non_repeated/non_repeat_challenge.ipynb @@ -0,0 +1,168 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "This notebook was prepared by [Lee Costello](https://github.com/betterin30days). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Challenge Notebook" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Find the first non-repeated character in a string. A repeating char is when the same character appears more than once in a row.\n", + "\n", + "* [Constraints](#Constraints)\n", + "* [Test Cases](#Test-Cases)\n", + "* [Algorithm](#Algorithm)\n", + "* [Code](#Code)\n", + "* [Unit Test](#Unit-Test)\n", + "* [Solution Notebook](#Solution-Notebook)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Constraints\n", + "\n", + "* Can we assume the string is ASCII?\n", + " * Yes\n", + " * Note: Unicode strings could require special handling depending on your language\n", + "* Is this case sensitive?\n", + " * Yes\n", + "* Is whitespace important? \n", + " * Yes\n", + "* Do we need to validate input?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* 'aabccd' -> 'b'\n", + "* 'abbccd' -> 'a'\n", + "* 'aabbadd' -> 'a'\n", + "* 'Aabccd' -> 'A'\n", + "* 'aabbccdd' -> None" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/non_repeated/non_repeat_solution.ipynb). If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Code" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": {}, + "outputs": [], + "source": [ + "class NonRepeat(object):\n", + "\n", + " def non_repeated_char(self, string):\n", + " # TODO: Implement me\n", + " pass" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Unit Test" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "\n", + "\n", + "**The following unit test is expected to fail until you solve the challenge.**" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": {}, + "outputs": [], + "source": [ + "# %load test_non_repeat.py\n", + "from nose.tools import assert_equal\n", + "\n", + "\n", + "class TestNonRepeat(object):\n", + "\n", + " def test_non_repeat(self, func):\n", + " assert_equal(func('aabccd'), 'b')\n", + " assert_equal(func('abbccd'), 'a')\n", + " assert_equal(func('aabbadd'), 'a')\n", + " assert_equal(func('aaab'), 'b')\n", + " assert_equal(func('Aabccd'), 'A')\n", + " assert_equal(func('aabbccdd'), None)\n", + " print('Success: test_non_repeat')\n", + "\n", + "def main():\n", + " test = TestNonRepeat()\n", + " nonrepeat = NonRepeat()\n", + " test.test_non_repeat(nonrepeat.non_repeated_char)\n", + "\n", + "\n", + "if __name__ == '__main__':\n", + " main()" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Solution Notebook\n", + "\n", + "Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/non_repeated/non_repeat_solution.ipynb) for a discussion on algorithms and code solutions." + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 3", + "language": "python", + "name": "python3" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 3 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython3", + "version": "3.5.2" + } + }, + "nbformat": 4, + "nbformat_minor": 1 +} diff --git a/arrays_strings/non_repeated/non_repeat_solution.ipynb b/arrays_strings/non_repeated/non_repeat_solution.ipynb new file mode 100644 index 0000000..d20ce20 --- /dev/null +++ b/arrays_strings/non_repeated/non_repeat_solution.ipynb @@ -0,0 +1,197 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "This notebook was prepared by [Lee Costello](https://github.com/betterin30days). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Solution Notebook" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Find the first non-repeated character in a string. A repeating char is when the same character appears more than once in a row.\n", + "\n", + "* [Constraints](#Constraints)\n", + "* [Test Cases](#Test-Cases)\n", + "* [Algorithm](#Algorithm)\n", + "* [Code](#Code)\n", + "* [Unit Test](#Unit-Test)\n", + "* [Solution Notebook](#Solution-Notebook)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Constraints\n", + "\n", + "* Can we assume the string is ASCII?\n", + " * Yes\n", + " * Note: Unicode strings could require special handling depending on your language\n", + "* Is this case sensitive?\n", + " * Yes\n", + "* Is whitespace important?\n", + " * Yes\n", + "* Do we need to validate input?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* 'aabccd' -> 'b'\n", + "* 'abbccd' -> 'a'\n", + "* 'aabbadd' -> 'a'\n", + "* 'Aabccd' -> 'A'\n", + "* 'aabbccdd' -> None" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "We only need to know if the current character is the same as the previous character, and if the last two characters were repeats.\n", + "* Iterate through the string once:\n", + " * if char == last_char: rep = True\n", + " * elif rep is True: rep = False\n", + " * elif last_char is not None: return last_char\n", + "* Perform a final check to account for the last character\n", + "\n", + "Complexity:\n", + "* Time: O(n)\n", + "* Space: O(1)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Code" + ] + }, + { + "cell_type": "code", + "execution_count": 1, + "metadata": { + "collapsed": true + }, + "outputs": [], + "source": [ + "class NonRepeat(object):\n", + "\n", + " def non_repeated_char(self, string):\n", + " assert isinstance(string, str)\n", + " last_char = None\n", + " is_repeating = False\n", + " for char in string:\n", + " if char == last_char:\n", + " is_repeating = True\n", + " elif is_repeating:\n", + " is_repeating = False\n", + " elif last_char is not None:\n", + " return last_char\n", + " last_char = char\n", + " if is_repeating is False:\n", + " return last_char" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Unit Test" + ] + }, + { + "cell_type": "code", + "execution_count": 2, + "metadata": {}, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Overwriting test_non_repeat.py\n" + ] + } + ], + "source": [ + "%%writefile test_non_repeat.py\n", + "from nose.tools import assert_equal\n", + "\n", + "\n", + "class TestNonRepeat(object):\n", + "\n", + " def test_non_repeat(self, func):\n", + " assert_equal(func('aabccd'), 'b')\n", + " assert_equal(func('abbccd'), 'a')\n", + " assert_equal(func('aabbadd'), 'a')\n", + " assert_equal(func('aaab'), 'b')\n", + " assert_equal(func('Aabccd'), 'A')\n", + " assert_equal(func('aabbccdd'), None)\n", + " print('Success: test_non_repeat')\n", + "\n", + "def main():\n", + " test = TestNonRepeat()\n", + " nonrepeat = NonRepeat()\n", + " test.test_non_repeat(nonrepeat.non_repeated_char)\n", + "\n", + "\n", + "if __name__ == '__main__':\n", + " main()" + ] + }, + { + "cell_type": "code", + "execution_count": 3, + "metadata": {}, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Success: test_non_repeat\n" + ] + } + ], + "source": [ + "%run -i test_non_repeat.py" + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 3", + "language": "python", + "name": "python3" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 3 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython3", + "version": "3.5.2" + } + }, + "nbformat": 4, + "nbformat_minor": 1 +} diff --git a/arrays_strings/non_repeated/test_non_repeat.py b/arrays_strings/non_repeated/test_non_repeat.py new file mode 100644 index 0000000..e9b0d39 --- /dev/null +++ b/arrays_strings/non_repeated/test_non_repeat.py @@ -0,0 +1,22 @@ +from nose.tools import assert_equal + + +class TestNonRepeat(object): + + def test_non_repeat(self, func): + assert_equal(func('aabccd'), 'b') + assert_equal(func('abbccd'), 'a') + assert_equal(func('aabbadd'), 'a') + assert_equal(func('aaab'), 'b') + assert_equal(func('Aabccd'), 'A') + assert_equal(func('aabbccdd'), None) + print('Success: test_non_repeat') + +def main(): + test = TestNonRepeat() + nonrepeat = NonRepeat() + test.test_non_repeat(nonrepeat.non_repeated_char) + + +if __name__ == '__main__': + main()