mirror of
https://github.com/donnemartin/interactive-coding-challenges.git
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Added delete mid challenge.
This commit is contained in:
Donne Martin
parent
001cab5697
commit
4c2c1d4391
0
linked_lists/delete_mid/__init__.py
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0
linked_lists/delete_mid/__init__.py
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192
linked_lists/delete_mid/delete_mid_challenge.ipynb
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192
linked_lists/delete_mid/delete_mid_challenge.ipynb
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@ -0,0 +1,192 @@
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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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"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges).</i></small>"
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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: Delete a node in the middle, given only access to that node.\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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"*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
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"\n",
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"* What if the final node is being deleted, for example a single node list? Do we make it a dummy with a NULL value?\n",
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" * Yes\n",
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"* Can we assume we already have a linked list class that can be used for this problem?\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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"* Delete on empty list -> None\n",
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"* Delete None -> None\n",
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"* Delete on one node -> [None]\n",
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"* Delete on multiple nodes"
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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/coding-challenges/blob/master/linked_lists/delete_mid/delete_mid_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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"%run ../linked_list/linked_list.py\n",
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"%load ../linked_list/linked_list.py"
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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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class MyLinkedList(LinkedList):\n",
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" \n",
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" def delete_node(self, node):\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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"# %load test_delete_mid.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 TestDeleteNode(object):\n",
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" \n",
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" def test_delete_node(self):\n",
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" print('Test: Empty list, null node to delete')\n",
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" linked_list = MyLinkedList(None)\n",
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" linked_list.delete_node(None)\n",
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" assert_equal(linked_list.get_all_data(), [])\n",
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"\n",
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" print('Test: One node')\n",
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" head = Node(2)\n",
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" linked_list = MyLinkedList(head)\n",
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" linked_list.delete_node(head)\n",
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" assert_equal(linked_list.get_all_data(), [None])\n",
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"\n",
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" print('Test: Multiple nodes')\n",
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" linked_list = MyLinkedList(None) \n",
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" node0 = linked_list.insert_to_front(1)\n",
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" node1 = linked_list.insert_to_front(3)\n",
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" node2 = linked_list.insert_to_front(4)\n",
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" node3 = linked_list.insert_to_front(1)\n",
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" linked_list.delete_node(node2)\n",
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" assert_equal(linked_list.get_all_data(), [1, 3, 1])\n",
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" \n",
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" print('Success: test_delete_node')\n",
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"\n",
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"def main():\n",
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" test = TestDeleteNode()\n",
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" test.test_delete_node()\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/coding-challenges/blob/master/linked_lists/delete_mid/delete_mid_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 2",
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"language": "python",
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"name": "python2"
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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": 2
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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": "ipython2",
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"version": "2.7.10"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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@ -4,7 +4,14 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
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"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges).</i></small>"
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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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@ -26,7 +33,7 @@
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"source": [
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"## Constraints\n",
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"\n",
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"*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
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"*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
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"\n",
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"* What if the final node is being deleted, for example a single node list? Do we make it a dummy with a NULL value?\n",
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" * Yes\n",
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@ -40,10 +47,10 @@
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"source": [
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"## Test Cases\n",
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"\n",
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"* Empty list\n",
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"* Null node to delete\n",
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"* One node\n",
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"* Multiple nodes"
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"* Delete on empty list -> None\n",
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"* Delete None -> None\n",
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"* Delete on one node -> [None]\n",
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"* Delete on multiple nodes"
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]
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},
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{
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@ -74,11 +81,11 @@
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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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"%run linked_list.py"
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"%run ../linked_list/linked_list.py"
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]
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},
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{
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@ -89,12 +96,8 @@
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},
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"outputs": [],
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"source": [
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"class Node(object):\n",
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" def __init__(self, data):\n",
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" self.data = data\n",
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" self.next = None\n",
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"\n",
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"class MyLinkedList(LinkedList):\n",
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" \n",
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" def delete_node(self, node):\n",
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" if self.head is None:\n",
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" return\n",
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@ -116,13 +119,6 @@
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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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"*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.*"
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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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@ -134,17 +130,17 @@
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Test: Empty list, null node to delete\n",
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"Test: One node\n",
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"Test: Multiple nodes\n",
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"Success: test_delete_node\n"
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"Overwriting test_delete_mid.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_delete_mid.py\n",
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"from nose.tools import assert_equal\n",
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"\n",
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"class Test(object):\n",
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"\n",
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"class TestDeleteNode(object):\n",
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" \n",
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" def test_delete_node(self):\n",
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" print('Test: Empty list, null node to delete')\n",
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" linked_list = MyLinkedList(None)\n",
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@ -168,9 +164,34 @@
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" \n",
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" print('Success: test_delete_node')\n",
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"\n",
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"def main():\n",
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" test = TestDeleteNode()\n",
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" test.test_delete_node()\n",
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" \n",
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"if __name__ == '__main__':\n",
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" test = Test()\n",
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" test.test_delete_node()"
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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": 4,
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"metadata": {
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"collapsed": false
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},
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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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"Test: Empty list, null node to delete\n",
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"Test: One node\n",
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"Test: Multiple nodes\n",
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"Success: test_delete_node\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_delete_mid.py"
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]
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}
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],
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34
linked_lists/delete_mid/test_delete_mid.py
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linked_lists/delete_mid/test_delete_mid.py
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from nose.tools import assert_equal
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class TestDeleteNode(object):
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def test_delete_node(self):
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print('Test: Empty list, null node to delete')
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linked_list = MyLinkedList(None)
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linked_list.delete_node(None)
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assert_equal(linked_list.get_all_data(), [])
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print('Test: One node')
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head = Node(2)
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linked_list = MyLinkedList(head)
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linked_list.delete_node(head)
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assert_equal(linked_list.get_all_data(), [None])
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print('Test: Multiple nodes')
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linked_list = MyLinkedList(None)
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node0 = linked_list.insert_to_front(1)
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node1 = linked_list.insert_to_front(3)
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node2 = linked_list.insert_to_front(4)
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node3 = linked_list.insert_to_front(1)
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linked_list.delete_node(node2)
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assert_equal(linked_list.get_all_data(), [1, 3, 1])
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print('Success: test_delete_node')
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def main():
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test = TestDeleteNode()
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test.test_delete_node()
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if __name__ == '__main__':
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main()
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