diff --git a/linked_lists/partition/__init__.py b/linked_lists/partition/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/linked_lists/partition/partition_challenge.ipynb b/linked_lists/partition/partition_challenge.ipynb new file mode 100644 index 0000000..5c41e38 --- /dev/null +++ b/linked_lists/partition/partition_challenge.ipynb @@ -0,0 +1,211 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Challenge Notebook" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Partition a linked list around a value x, such that all nodes less than x come before all nodes greater than or equal to x.\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", + "*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n", + "\n", + "* Can we create additional data structures?\n", + " * Yes\n", + "* Do you expect the function to return a new list?\n", + " * Yes\n", + "* Can we assume the input x is valid?\n", + " * Yes\n", + "* Can we assume we already have a linked list class that can be used for this problem?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* Empty list -> []\n", + "* One element list -> [element]\n", + "* Left linked list is empty\n", + "* Right linked list is empty\n", + "* General case\n", + " * Partition = 10\n", + " * Input: 4, 3, 7, 8, 10, 1, 10, 12\n", + " * Output: 4, 3, 7, 8, 1, 10, 10, 12" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/coding-challenges/blob/master/linked_lists/partition/partition_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": { + "collapsed": true + }, + "outputs": [], + "source": [ + "%run ../linked_list/linked_list.py\n", + "%load ../linked_list/linked_list.py" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": false + }, + "outputs": [], + "source": [ + "class MyLinkedList(LinkedList):\n", + " \n", + " def partition(self, data):\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": { + "collapsed": false + }, + "outputs": [], + "source": [ + "# %load test_partition.py\n", + "from nose.tools import assert_equal\n", + "\n", + "\n", + "class TestPartition(object):\n", + " \n", + " def test_partition(self):\n", + " print('Test: Empty list')\n", + " linked_list = MyLinkedList(None)\n", + " linked_list.partition(10)\n", + " assert_equal(linked_list.get_all_data(), [])\n", + "\n", + " print('Test: One element list, left list empty')\n", + " linked_list = MyLinkedList(Node(5))\n", + " linked_list.partition(0)\n", + " assert_equal(linked_list.get_all_data(), [5])\n", + "\n", + " print('Test: Right list is empty')\n", + " linked_list = MyLinkedList(Node(5))\n", + " linked_list.partition(10)\n", + " assert_equal(linked_list.get_all_data(), [5])\n", + "\n", + " print('Test: General case')\n", + " # Partition = 10\n", + " # Input: 4, 3, 7, 8, 10, 1, 10, 12\n", + " # Output: 4, 3, 7, 8, 1, 10, 10, 12\n", + " linked_list = MyLinkedList(Node(12))\n", + " linked_list.insert_to_front(10)\n", + " linked_list.insert_to_front(1)\n", + " linked_list.insert_to_front(10)\n", + " linked_list.insert_to_front(8)\n", + " linked_list.insert_to_front(7)\n", + " linked_list.insert_to_front(3)\n", + " linked_list.insert_to_front(4)\n", + " partitioned_list = linked_list.partition(10)\n", + " assert_equal(partitioned_list.get_all_data(), \n", + " [4, 3, 7, 8, 1, 10, 10, 12])\n", + " \n", + " print('Success: test_partition')\n", + "\n", + "def main():\n", + " test = TestPartition()\n", + " test.test_partition()\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/coding-challenges/blob/master/linked_lists/partition/partition_solution.ipynb) for a discussion on algorithms and code solutions." + ] + } + ], + "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/linked_lists/partition/partition_solution.ipynb b/linked_lists/partition/partition_solution.ipynb index ba82f75..dcaad53 100644 --- a/linked_lists/partition/partition_solution.ipynb +++ b/linked_lists/partition/partition_solution.ipynb @@ -4,7 +4,14 @@ "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)." + "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Solution Notebook" ] }, { @@ -26,7 +33,7 @@ "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", + "*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n", "\n", "* Can we create additional data structures?\n", " * Yes\n", @@ -44,8 +51,8 @@ "source": [ "## Test Cases\n", "\n", - "* Empty list\n", - "* One element list\n", + "* Empty list -> []\n", + "* One element list -> [element]\n", "* Left linked list is empty\n", "* Right linked list is empty\n", "* General case\n", @@ -86,7 +93,7 @@ }, "outputs": [], "source": [ - "%run linked_list.py" + "%run ../linked_list/linked_list.py" ] }, { @@ -98,6 +105,7 @@ "outputs": [], "source": [ "class MyLinkedList(LinkedList):\n", + " \n", " def partition(self, data):\n", " if self.head is None:\n", " return\n", @@ -130,13 +138,6 @@ "## Unit Test" ] }, - { - "cell_type": "markdown", - "metadata": {}, - "source": [ - "*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.*" - ] - }, { "cell_type": "code", "execution_count": 3, @@ -148,18 +149,17 @@ "name": "stdout", "output_type": "stream", "text": [ - "Test: Empty list\n", - "Test: One element list, left list empty\n", - "Test: Right list is empty\n", - "Test: General case\n", - "Success: test_partition\n" + "Overwriting test_partition.py\n" ] } ], "source": [ + "%%writefile test_partition.py\n", "from nose.tools import assert_equal\n", "\n", - "class Test(object):\n", + "\n", + "class TestPartition(object):\n", + " \n", " def test_partition(self):\n", " print('Test: Empty list')\n", " linked_list = MyLinkedList(None)\n", @@ -194,9 +194,35 @@ " \n", " print('Success: test_partition')\n", "\n", + "def main():\n", + " test = TestPartition()\n", + " test.test_partition()\n", + " \n", "if __name__ == '__main__':\n", - " test = Test()\n", - " test.test_partition()" + " main()" + ] + }, + { + "cell_type": "code", + "execution_count": 4, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Test: Empty list\n", + "Test: One element list, left list empty\n", + "Test: Right list is empty\n", + "Test: General case\n", + "Success: test_partition\n" + ] + } + ], + "source": [ + "run -i test_partition.py" ] } ], diff --git a/linked_lists/partition/test_partition.py b/linked_lists/partition/test_partition.py new file mode 100644 index 0000000..c3d17e6 --- /dev/null +++ b/linked_lists/partition/test_partition.py @@ -0,0 +1,45 @@ +from nose.tools import assert_equal + + +class TestPartition(object): + + def test_partition(self): + print('Test: Empty list') + linked_list = MyLinkedList(None) + linked_list.partition(10) + assert_equal(linked_list.get_all_data(), []) + + print('Test: One element list, left list empty') + linked_list = MyLinkedList(Node(5)) + linked_list.partition(0) + assert_equal(linked_list.get_all_data(), [5]) + + print('Test: Right list is empty') + linked_list = MyLinkedList(Node(5)) + linked_list.partition(10) + assert_equal(linked_list.get_all_data(), [5]) + + print('Test: General case') + # Partition = 10 + # Input: 4, 3, 7, 8, 10, 1, 10, 12 + # Output: 4, 3, 7, 8, 1, 10, 10, 12 + linked_list = MyLinkedList(Node(12)) + linked_list.insert_to_front(10) + linked_list.insert_to_front(1) + linked_list.insert_to_front(10) + linked_list.insert_to_front(8) + linked_list.insert_to_front(7) + linked_list.insert_to_front(3) + linked_list.insert_to_front(4) + partitioned_list = linked_list.partition(10) + assert_equal(partitioned_list.get_all_data(), + [4, 3, 7, 8, 1, 10, 10, 12]) + + print('Success: test_partition') + +def main(): + test = TestPartition() + test.test_partition() + +if __name__ == '__main__': + main() \ No newline at end of file