Added selection sort challenge.

This commit is contained in:
Donne Martin 2015-07-01 06:47:36 -04:00
parent 4a0a2c1267
commit 3a44e384ef
4 changed files with 251 additions and 19 deletions

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@ -0,0 +1,167 @@
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<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>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Problem: Implement selection sort.\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",
"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
" * Yes"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Test Cases\n",
"\n",
"* Empty input -> []\n",
"* One element -> [element]\n",
"* Two or more elements"
]
},
{
"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": false
},
"outputs": [],
"source": [
"def selection_sort(data, start=0):\n",
" # TODO: Implement me (recursive)\n",
" pass"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def selection_sort_iterative(data):\n",
" # TODO: Implement me (iterative)\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_selection_sort.py\n",
"from nose.tools import assert_equal\n",
"\n",
"\n",
"class TestSelectionSort(object):\n",
" \n",
" def test_selection_sort(self, func):\n",
" print('Empty input')\n",
" data = []\n",
" func(data)\n",
" assert_equal(data, [])\n",
"\n",
" print('One element')\n",
" data = [5]\n",
" func(data)\n",
" assert_equal(data, [5])\n",
"\n",
" print('Two or more elements')\n",
" data = [5, 1, 7, 2, 6, -3, 5, 7, -1]\n",
" func(data)\n",
" assert_equal(data, sorted(data))\n",
" \n",
" print('Success: test_selection_sort\\n')\n",
"\n",
"def main():\n",
" test = TestSelectionSort()\n",
" test.test_selection_sort(selection_sort)\n",
" try:\n",
" test.test_selection_sort(selection_sort_iterative)\n",
" except NameError:\n",
" # Alternate solutions are only defined\n",
" # in the solutions file\n",
" pass\n",
"\n",
"if __name__ == '__main__':\n",
" main()"
]
}
],
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"name": "python2"
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@ -28,7 +28,7 @@
"\n",
"*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
"\n",
"* Are you looking for a naiive solution (ie not stable, not based on a heap)?\n",
"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
" * Yes"
]
},
@ -38,8 +38,8 @@
"source": [
"## Test Cases\n",
"\n",
"* Empty input\n",
"* One element\n",
"* Empty input -> []\n",
"* One element -> [element]\n",
"* Two or more elements"
]
},
@ -98,10 +98,10 @@
},
"outputs": [],
"source": [
"def selection_sort_recursive(data, start=0):\n",
"def selection_sort(data, start=0):\n",
" if start < len(data) - 1:\n",
" swap(data, start, find_min_index(data, start))\n",
" selection_sort_recursive(data, start+1)"
" selection_sort(data, start+1)"
]
},
{
@ -139,23 +139,17 @@
"name": "stdout",
"output_type": "stream",
"text": [
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n",
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n"
"Overwriting test_selection_sort.py\n"
]
}
],
"source": [
"%%writefile test_selection_sort.py\n",
"from nose.tools import assert_equal\n",
"\n",
"class Test(object):\n",
"\n",
"class TestSelectionSort(object):\n",
" \n",
" def test_selection_sort(self, func):\n",
" print('Empty input')\n",
" data = []\n",
@ -174,10 +168,46 @@
" \n",
" print('Success: test_selection_sort\\n')\n",
"\n",
"def main():\n",
" test = TestSelectionSort()\n",
" test.test_selection_sort(selection_sort)\n",
" try:\n",
" test.test_selection_sort(selection_sort_iterative)\n",
" except NameError:\n",
" # Alternate solutions are only defined\n",
" # in the solutions file\n",
" pass\n",
"\n",
"if __name__ == '__main__':\n",
" test = Test()\n",
" test.test_selection_sort(selection_sort_recursive)\n",
" test.test_selection_sort(selection_sort_iterative)"
" main()"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n",
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n"
]
}
],
"source": [
"%run -i test_selection_sort.py"
]
}
],

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@ -0,0 +1,35 @@
from nose.tools import assert_equal
class TestSelectionSort(object):
def test_selection_sort(self, func):
print('Empty input')
data = []
func(data)
assert_equal(data, [])
print('One element')
data = [5]
func(data)
assert_equal(data, [5])
print('Two or more elements')
data = [5, 1, 7, 2, 6, -3, 5, 7, -1]
func(data)
assert_equal(data, sorted(data))
print('Success: test_selection_sort\n')
def main():
test = TestSelectionSort()
test.test_selection_sort(selection_sort)
try:
test.test_selection_sort(selection_sort_iterative)
except NameError:
# Alternate solutions are only defined
# in the solutions file
pass
if __name__ == '__main__':
main()