mirror of
https://github.com/donnemartin/interactive-coding-challenges.git
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Initial commit for new challenge: Non repeating char
This commit is contained in:
betterin30days
parent
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commit
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0
arrays_strings/non_repeated/__init__.py
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0
arrays_strings/non_repeated/__init__.py
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168
arrays_strings/non_repeated/non_repeat_challenge.ipynb
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168
arrays_strings/non_repeated/non_repeat_challenge.ipynb
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@ -0,0 +1,168 @@
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"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)."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Challenge Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 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",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)\n",
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"* [Solution Notebook](#Solution-Notebook)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Constraints\n",
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"\n",
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"* Can we assume the string is ASCII?\n",
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" * Yes\n",
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" * Note: Unicode strings could require special handling depending on your language\n",
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"* Is this case sensitive?\n",
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" * Yes\n",
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"* Is whitespace important? \n",
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" * Yes\n",
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"* Do we need to validate input?\n",
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" * Yes"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Test Cases\n",
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"\n",
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"* 'aabccd' -> 'b'\n",
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"* 'abbccd' -> 'a'\n",
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"* 'aabbadd' -> 'a'\n",
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"* 'Aabccd' -> 'A'\n",
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"* 'aabbccdd' -> None"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"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."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"class NonRepeat(object):\n",
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"\n",
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" def non_repeated_char(self, string):\n",
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" # TODO: Implement me\n",
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" pass"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Unit Test"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"\n",
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"\n",
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"**The following unit test is expected to fail until you solve the challenge.**"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# %load test_non_repeat.py\n",
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"from nose.tools import assert_equal\n",
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"\n",
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"\n",
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"class TestNonRepeat(object):\n",
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"\n",
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" def test_non_repeat(self, func):\n",
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" assert_equal(func('aabccd'), 'b')\n",
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" assert_equal(func('abbccd'), 'a')\n",
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" assert_equal(func('aabbadd'), 'a')\n",
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" assert_equal(func('aaab'), 'b')\n",
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" assert_equal(func('Aabccd'), 'A')\n",
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" assert_equal(func('aabbccdd'), None)\n",
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" print('Success: test_non_repeat')\n",
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"\n",
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"def main():\n",
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" test = TestNonRepeat()\n",
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" nonrepeat = NonRepeat()\n",
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" test.test_non_repeat(nonrepeat.non_repeated_char)\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Solution Notebook\n",
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"\n",
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"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."
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.5.2"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 1
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}
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197
arrays_strings/non_repeated/non_repeat_solution.ipynb
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197
arrays_strings/non_repeated/non_repeat_solution.ipynb
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@ -0,0 +1,197 @@
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"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)."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Solution Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 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",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)\n",
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"* [Solution Notebook](#Solution-Notebook)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Constraints\n",
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"\n",
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"* Can we assume the string is ASCII?\n",
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" * Yes\n",
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" * Note: Unicode strings could require special handling depending on your language\n",
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"* Is this case sensitive?\n",
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" * Yes\n",
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"* Is whitespace important?\n",
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" * Yes\n",
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"* Do we need to validate input?\n",
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" * Yes"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Test Cases\n",
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"\n",
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"* 'aabccd' -> 'b'\n",
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"* 'abbccd' -> 'a'\n",
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"* 'aabbadd' -> 'a'\n",
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"* 'Aabccd' -> 'A'\n",
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"* 'aabbccdd' -> None"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"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",
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"* Iterate through the string once:\n",
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" * if char == last_char: rep = True\n",
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" * elif rep is True: rep = False\n",
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" * elif last_char is not None: return last_char\n",
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"* Perform a final check to account for the last character\n",
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"\n",
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"Complexity:\n",
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"* Time: O(n)\n",
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"* Space: O(1)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"class NonRepeat(object):\n",
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"\n",
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" def non_repeated_char(self, string):\n",
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" assert isinstance(string, str)\n",
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" last_char = None\n",
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" is_repeating = False\n",
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" for char in string:\n",
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" if char == last_char:\n",
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" is_repeating = True\n",
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" elif is_repeating:\n",
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" is_repeating = False\n",
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" elif last_char is not None:\n",
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" return last_char\n",
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" last_char = char\n",
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" if is_repeating is False:\n",
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" return last_char"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Unit Test"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Overwriting test_non_repeat.py\n"
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]
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}
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],
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"source": [
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"%%writefile test_non_repeat.py\n",
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"from nose.tools import assert_equal\n",
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"\n",
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"\n",
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"class TestNonRepeat(object):\n",
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"\n",
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" def test_non_repeat(self, func):\n",
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" assert_equal(func('aabccd'), 'b')\n",
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" assert_equal(func('abbccd'), 'a')\n",
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" assert_equal(func('aabbadd'), 'a')\n",
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" assert_equal(func('aaab'), 'b')\n",
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" assert_equal(func('Aabccd'), 'A')\n",
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" assert_equal(func('aabbccdd'), None)\n",
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" print('Success: test_non_repeat')\n",
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"\n",
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"def main():\n",
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" test = TestNonRepeat()\n",
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" nonrepeat = NonRepeat()\n",
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" test.test_non_repeat(nonrepeat.non_repeated_char)\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Success: test_non_repeat\n"
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]
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}
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],
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"source": [
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"%run -i test_non_repeat.py"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.5.2"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 1
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}
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22
arrays_strings/non_repeated/test_non_repeat.py
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22
arrays_strings/non_repeated/test_non_repeat.py
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@ -0,0 +1,22 @@
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from nose.tools import assert_equal
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class TestNonRepeat(object):
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def test_non_repeat(self, func):
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assert_equal(func('aabccd'), 'b')
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assert_equal(func('abbccd'), 'a')
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assert_equal(func('aabbadd'), 'a')
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assert_equal(func('aaab'), 'b')
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assert_equal(func('Aabccd'), 'A')
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assert_equal(func('aabbccdd'), None)
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print('Success: test_non_repeat')
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def main():
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test = TestNonRepeat()
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nonrepeat = NonRepeat()
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test.test_non_repeat(nonrepeat.non_repeated_char)
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if __name__ == '__main__':
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main()
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