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https://github.com/donnemartin/interactive-coding-challenges.git
synced 2024-03-22 13:11:13 +08:00
Added stack sorting challenge.
This commit is contained in:
Donne Martin
parent
0b5acdb52f
commit
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0
stacks_queues/sort_stack/__init__.py
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stacks_queues/sort_stack/__init__.py
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177
stacks_queues/sort_stack/sort_stack_challenge.ipynb
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stacks_queues/sort_stack/sort_stack_challenge.ipynb
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@ -0,0 +1,177 @@
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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://bit.ly/code-notes).</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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"## Problem: Sort a stack. You can use another stack as a buffer.\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)"
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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 often intentionally 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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"* When sorted, should the largest element be at the top or bottom?\n",
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" * Top\n",
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"* Can you have duplicate values like 5, 5?\n",
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" * Yes\n",
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"* Can we assume we already have a stack 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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"* Empty stack -> None\n",
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"* One element stack\n",
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"* Two or more element stack (general case)\n",
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"* Already sorted stack"
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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. 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": true
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},
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"outputs": [],
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"source": [
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"%run ../stack/stack.py\n",
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"%load ../stack/stack.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 MyStack(Stack):\n",
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" \n",
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" def sort(self):\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\n",
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"\n",
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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.*\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_sort_stack.py\n",
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"from random import randint\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 TestSortStack(object):\n",
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" \n",
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" def get_sorted_stack(self, numbers):\n",
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" stack = MyStack()\n",
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" for x in numbers:\n",
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" stack.push(x)\n",
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" sorted_stack = stack.sort()\n",
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" return sorted_stack\n",
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"\n",
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" def test_sort_stack(self):\n",
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" print('Test: Empty stack')\n",
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" sorted_stack = self.get_sorted_stack([])\n",
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" assert_equal(sorted_stack.pop(), None)\n",
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"\n",
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" print('Test: One element stack')\n",
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" sorted_stack = self.get_sorted_stack([1])\n",
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" assert_equal(sorted_stack.pop(), 1)\n",
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"\n",
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" print('Test: Two or more element stack (general case)')\n",
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" num_items = 10\n",
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" numbers = [randint(0, 10) for x in xrange(num_items)]\n",
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" sorted_stack = self.get_sorted_stack(numbers)\n",
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" sorted_numbers = []\n",
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" for _ in xrange(num_items):\n",
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" sorted_numbers.append(sorted_stack.pop())\n",
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" assert_equal(sorted_numbers, sorted(numbers, reverse=True))\n",
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" \n",
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" print('Success: test_sort_stack')\n",
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"\n",
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"def main():\n",
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" test = TestSortStack()\n",
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" test.test_sort_stack()\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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"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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@ -42,7 +42,7 @@
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"source": [
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"## Test Cases\n",
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"\n",
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"* Empty stack\n",
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"* Empty stack -> None\n",
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"* One element stack\n",
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"* Two or more element stack (general case)\n",
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"* Already sorted stack"
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@ -82,7 +82,8 @@
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},
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"outputs": [],
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"source": [
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"%run stack.py"
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"%run ../stack/stack.py\n",
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"%load ../stack/stack.py"
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]
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},
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{
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@ -94,6 +95,7 @@
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"outputs": [],
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"source": [
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"class MyStack(Stack):\n",
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" \n",
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" def sort(self):\n",
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" buff = MyStack()\n",
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" while not self.is_empty():\n",
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@ -124,18 +126,18 @@
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Test: Empty stack\n",
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"Test: One element stack\n",
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"Test: Two or more element stack (general case)\n",
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"Success: test_sort_stack\n"
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"Overwriting test_sort_stack.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_sort_stack.py\n",
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"from random import randint\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 TestSortStack(object):\n",
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" \n",
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" def get_sorted_stack(self, numbers):\n",
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" stack = MyStack()\n",
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" for x in numbers:\n",
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@ -163,9 +165,34 @@
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" \n",
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" print('Success: test_sort_stack')\n",
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"\n",
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"def main():\n",
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" test = TestSortStack()\n",
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" test.test_sort_stack()\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_sort_stack()"
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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 stack\n",
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"Test: One element stack\n",
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"Test: Two or more element stack (general case)\n",
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"Success: test_sort_stack\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_sort_stack.py"
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]
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}
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],
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39
stacks_queues/sort_stack/test_sort_stack.py
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stacks_queues/sort_stack/test_sort_stack.py
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from random import randint
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from nose.tools import assert_equal
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class TestSortStack(object):
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def get_sorted_stack(self, numbers):
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stack = MyStack()
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for x in numbers:
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stack.push(x)
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sorted_stack = stack.sort()
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return sorted_stack
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def test_sort_stack(self):
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print('Test: Empty stack')
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sorted_stack = self.get_sorted_stack([])
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assert_equal(sorted_stack.pop(), None)
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print('Test: One element stack')
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sorted_stack = self.get_sorted_stack([1])
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assert_equal(sorted_stack.pop(), 1)
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print('Test: Two or more element stack (general case)')
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num_items = 10
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numbers = [randint(0, 10) for x in xrange(num_items)]
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sorted_stack = self.get_sorted_stack(numbers)
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sorted_numbers = []
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for _ in xrange(num_items):
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sorted_numbers.append(sorted_stack.pop())
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assert_equal(sorted_numbers, sorted(numbers, reverse=True))
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print('Success: test_sort_stack')
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def main():
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test = TestSortStack()
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test.test_sort_stack()
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if __name__ == '__main__':
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main()
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