From 0e6419e3658ddedfb4dfb02e950a64b8cd5e21b3 Mon Sep 17 00:00:00 2001 From: Donne Martin Date: Wed, 1 Jul 2015 06:48:27 -0400 Subject: [PATCH] Added stack sorting challenge. --- stacks_queues/sort_stack/__init__.py | 0 .../sort_stack/sort_stack_challenge.ipynb | 177 ++++++++++++++++++ .../sort_stack/sort_stack_solution.ipynb | 45 ++++- stacks_queues/sort_stack/test_sort_stack.py | 39 ++++ 4 files changed, 252 insertions(+), 9 deletions(-) create mode 100644 stacks_queues/sort_stack/__init__.py create mode 100644 stacks_queues/sort_stack/sort_stack_challenge.ipynb create mode 100644 stacks_queues/sort_stack/test_sort_stack.py diff --git a/stacks_queues/sort_stack/__init__.py b/stacks_queues/sort_stack/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/stacks_queues/sort_stack/sort_stack_challenge.ipynb b/stacks_queues/sort_stack/sort_stack_challenge.ipynb new file mode 100644 index 0000000..baac67c --- /dev/null +++ b/stacks_queues/sort_stack/sort_stack_challenge.ipynb @@ -0,0 +1,177 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Sort a stack. You can use another stack as a buffer.\n", + "\n", + "* [Constraints](#Constraints)\n", + "* [Test Cases](#Test-Cases)\n", + "* [Algorithm](#Algorithm)\n", + "* [Code](#Code)\n", + "* [Unit Test](#Unit-Test)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Constraints\n", + "\n", + "*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n", + "\n", + "* When sorted, should the largest element be at the top or bottom?\n", + " * Top\n", + "* Can you have duplicate values like 5, 5?\n", + " * Yes\n", + "* Can we assume we already have a stack class that can be used for this problem?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* Empty stack -> None\n", + "* One element stack\n", + "* Two or more element stack (general case)\n", + "* Already sorted stack" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "Refer to the solution notebook. 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": { + "collapsed": true + }, + "outputs": [], + "source": [ + "%run ../stack/stack.py\n", + "%load ../stack/stack.py" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": false + }, + "outputs": [], + "source": [ + "class MyStack(Stack):\n", + " \n", + " def sort(self):\n", + " # TODO: Implement me\n", + " pass" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Unit Test\n", + "\n", + "*It is important to identify and run through general and edge cases from the [Test Cases](#Test-Cases) section by hand. You generally will not be asked to write a unit test like what is shown below.*\n", + "\n", + "**The following unit test is expected to fail until you solve the challenge.**" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": false + }, + "outputs": [], + "source": [ + "# %load test_sort_stack.py\n", + "from random import randint\n", + "from nose.tools import assert_equal\n", + "\n", + "\n", + "class TestSortStack(object):\n", + " \n", + " def get_sorted_stack(self, numbers):\n", + " stack = MyStack()\n", + " for x in numbers:\n", + " stack.push(x)\n", + " sorted_stack = stack.sort()\n", + " return sorted_stack\n", + "\n", + " def test_sort_stack(self):\n", + " print('Test: Empty stack')\n", + " sorted_stack = self.get_sorted_stack([])\n", + " assert_equal(sorted_stack.pop(), None)\n", + "\n", + " print('Test: One element stack')\n", + " sorted_stack = self.get_sorted_stack([1])\n", + " assert_equal(sorted_stack.pop(), 1)\n", + "\n", + " print('Test: Two or more element stack (general case)')\n", + " num_items = 10\n", + " numbers = [randint(0, 10) for x in xrange(num_items)]\n", + " sorted_stack = self.get_sorted_stack(numbers)\n", + " sorted_numbers = []\n", + " for _ in xrange(num_items):\n", + " sorted_numbers.append(sorted_stack.pop())\n", + " assert_equal(sorted_numbers, sorted(numbers, reverse=True))\n", + " \n", + " print('Success: test_sort_stack')\n", + "\n", + "def main():\n", + " test = TestSortStack()\n", + " test.test_sort_stack()\n", + "\n", + "if __name__ == '__main__':\n", + " main()" + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 2", + "language": "python", + "name": "python2" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 2 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython2", + "version": "2.7.10" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/stacks_queues/sort_stack/sort_stack_solution.ipynb b/stacks_queues/sort_stack/sort_stack_solution.ipynb index 3332870..fae0823 100644 --- a/stacks_queues/sort_stack/sort_stack_solution.ipynb +++ b/stacks_queues/sort_stack/sort_stack_solution.ipynb @@ -42,7 +42,7 @@ "source": [ "## Test Cases\n", "\n", - "* Empty stack\n", + "* Empty stack -> None\n", "* One element stack\n", "* Two or more element stack (general case)\n", "* Already sorted stack" @@ -82,7 +82,8 @@ }, "outputs": [], "source": [ - "%run stack.py" + "%run ../stack/stack.py\n", + "%load ../stack/stack.py" ] }, { @@ -94,6 +95,7 @@ "outputs": [], "source": [ "class MyStack(Stack):\n", + " \n", " def sort(self):\n", " buff = MyStack()\n", " while not self.is_empty():\n", @@ -124,18 +126,18 @@ "name": "stdout", "output_type": "stream", "text": [ - "Test: Empty stack\n", - "Test: One element stack\n", - "Test: Two or more element stack (general case)\n", - "Success: test_sort_stack\n" + "Overwriting test_sort_stack.py\n" ] } ], "source": [ + "%%writefile test_sort_stack.py\n", "from random import randint\n", "from nose.tools import assert_equal\n", "\n", - "class Test(object):\n", + "\n", + "class TestSortStack(object):\n", + " \n", " def get_sorted_stack(self, numbers):\n", " stack = MyStack()\n", " for x in numbers:\n", @@ -163,9 +165,34 @@ " \n", " print('Success: test_sort_stack')\n", "\n", + "def main():\n", + " test = TestSortStack()\n", + " test.test_sort_stack()\n", + "\n", "if __name__ == '__main__':\n", - " test = Test()\n", - " test.test_sort_stack()" + " main()" + ] + }, + { + "cell_type": "code", + "execution_count": 4, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Test: Empty stack\n", + "Test: One element stack\n", + "Test: Two or more element stack (general case)\n", + "Success: test_sort_stack\n" + ] + } + ], + "source": [ + "%run -i test_sort_stack.py" ] } ], diff --git a/stacks_queues/sort_stack/test_sort_stack.py b/stacks_queues/sort_stack/test_sort_stack.py new file mode 100644 index 0000000..3522cc1 --- /dev/null +++ b/stacks_queues/sort_stack/test_sort_stack.py @@ -0,0 +1,39 @@ +from random import randint +from nose.tools import assert_equal + + +class TestSortStack(object): + + def get_sorted_stack(self, numbers): + stack = MyStack() + for x in numbers: + stack.push(x) + sorted_stack = stack.sort() + return sorted_stack + + def test_sort_stack(self): + print('Test: Empty stack') + sorted_stack = self.get_sorted_stack([]) + assert_equal(sorted_stack.pop(), None) + + print('Test: One element stack') + sorted_stack = self.get_sorted_stack([1]) + assert_equal(sorted_stack.pop(), 1) + + print('Test: Two or more element stack (general case)') + num_items = 10 + numbers = [randint(0, 10) for x in xrange(num_items)] + sorted_stack = self.get_sorted_stack(numbers) + sorted_numbers = [] + for _ in xrange(num_items): + sorted_numbers.append(sorted_stack.pop()) + assert_equal(sorted_numbers, sorted(numbers, reverse=True)) + + print('Success: test_sort_stack') + +def main(): + test = TestSortStack() + test.test_sort_stack() + +if __name__ == '__main__': + main() \ No newline at end of file