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Update selection sort challenge (#131)

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Update constraints, test cases, code, and tests.
This commit is contained in:
Donne Martin 2016-12-16 07:52:10 -05:00 committed by GitHub
parent bb56b63c39
commit daa7fba255
3 changed files with 90 additions and 126 deletions
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47
sorting_searching/selection_sort/selection_sort_challenge.ipynb
View File

@ -37,6 +37,10 @@
"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
" * Yes\n",
"* Are duplicates allowed?\n",
" * Yes\n",
"* Can we assume the input is valid?\n",
" * No\n",
"* Can we assume this fits memory?\n",
" * Yes"
]
},
@ -46,7 +50,7 @@
"source": [
"## Test Cases\n",
"\n",
"* None -> None\n",
"* None -> Exception\n",
"* Empty input -> []\n",
"* One element -> [element]\n",
"* Two or more elements"
@ -76,24 +80,13 @@
},
"outputs": [],
"source": [
"def selection_sort(data, start=0):\n",
"class SelectionSort(object):\n",
"\n",
" def sort(self, data):\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": {},
@ -114,41 +107,35 @@
"outputs": [],
"source": [
"# %load test_selection_sort.py\n",
"from nose.tools import assert_equal\n",
"from nose.tools import assert_equal, assert_raises\n",
"\n",
"\n",
"class TestSelectionSort(object):\n",
"\n",
" def test_selection_sort(self, func):\n",
" print('None input')\n",
" data = None\n",
" func(data)\n",
" assert_equal(data, None)\n",
" assert_raises(TypeError, func, None)\n",
"\n",
" print('Empty input')\n",
" data = []\n",
" func(data)\n",
" assert_equal(data, [])\n",
" assert_equal(func([]), [])\n",
"\n",
" print('One element')\n",
" data = [5]\n",
" func(data)\n",
" assert_equal(data, [5])\n",
" assert_equal(func([5]), [5])\n",
"\n",
" print('Two or more elements')\n",
" data = [5, 1, 7, 2, 6, -3, 5, 7, -10]\n",
" func(data)\n",
" assert_equal(data, sorted(data))\n",
" assert_equal(func(data), sorted(data))\n",
"\n",
" print('Success: test_selection_sort\\n')\n",
"\n",
"\n",
"def main():\n",
" test = TestSelectionSort()\n",
" test.test_selection_sort(selection_sort)\n",
" selection_sort = SelectionSort()\n",
" test.test_selection_sort(selection_sort.sort)\n",
" try:\n",
" test.test_selection_sort(selection_sort_recursive)\n",
" test.test_selection_sort(selection_sort_iterative_alt)\n",
" test.test_selection_sort(selection_sort.sort_recursive)\n",
" test.test_selection_sort(selection_sort.sor_iterative_alt)\n",
" except NameError:\n",
" # Alternate solutions are only defined\n",
" # in the solutions file\n",

127
sorting_searching/selection_sort/selection_sort_solution.ipynb
View File

@ -36,6 +36,10 @@
"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
" * Yes\n",
"* Are duplicates allowed?\n",
" * Yes\n",
"* Can we assume the input is valid?\n",
" * No\n",
"* Can we assume this fits memory?\n",
" * Yes"
]
},
@ -45,7 +49,7 @@
"source": [
"## Test Cases\n",
"\n",
"* None -> None\n",
"* None -> Exception\n",
"* [] -> []\n",
"* One element -> [element]\n",
"* Two or more elements"
@ -87,64 +91,57 @@
},
"outputs": [],
"source": [
"def selection_sort(data):\n",
" if data is None or len(data) < 2:\n",
" return\n",
"class SelectionSort(object):\n",
"\n",
" def sort(self, data):\n",
" if data is None:\n",
" raise TypeError('data cannot be None')\n",
" if len(data) < 2:\n",
" return data\n",
" for i in range(len(data)-1):\n",
" min_index = i\n",
" for j in range(i+1, len(data)):\n",
" if data[j] < data[min_index]:\n",
" min_index = j\n",
" data[i], data[min_index] = data[min_index], data[i]"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Below are alternate solutions with helper functions:"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"def find_min_index(data, start):\n",
" # Raises an exception if: \n",
" # -data is None\n",
" # -start >= len(data) - 1\n",
" if data[min_index] < data[i]:\n",
" data[i], data[min_index] = data[min_index], data[i]\n",
" return data\n",
"\n",
" def sort_iterative_alt(self, data):\n",
" if data is None:\n",
" raise TypeError('data cannot be None')\n",
" if len(data) < 2:\n",
" return data\n",
" for i in range(len(data)-1):\n",
" self._swap(data, i, self._find_min_index(data, i))\n",
" return data\n",
"\n",
" def sort_recursive(self, data, start=0):\n",
" if data is None:\n",
" raise TypeError('data cannot be None')\n",
" if len(data) < 2:\n",
" return data\n",
" return self._sort_recursive(data, start)\n",
"\n",
" def _sort_recursive(self, data, start):\n",
" if data is None:\n",
" return\n",
" if start < len(data) - 1:\n",
" swap(data, start, self._find_min_index(data, start))\n",
" self._sort_recursive(data, start+1)\n",
" return data\n",
"\n",
" def _find_min_index(self, data, start):\n",
" min_index = start\n",
" for i in range(start+1, len(data)):\n",
" if data[i] < data[min_index]:\n",
" min_index = i\n",
" return min_index\n",
"\n",
"\n",
"def swap(data, i, j):\n",
" # Raises an exception if: \n",
" # -data is None\n",
" # -i or j are >= len(data)\n",
" def _swap(self, data, i, j):\n",
" if i != j:\n",
" data[i], data[j] = data[j], data[i]\n",
"\n",
"\n",
"def selection_sort_recursive(data, start=0):\n",
" if data is None:\n",
" return\n",
" if start < len(data) - 1:\n",
" swap(data, start, find_min_index(data, start))\n",
" selection_sort_recursive(data, start+1)\n",
"\n",
"\n",
"def selection_sort_iterative_alt(data):\n",
" if data is None or len(data) < 2:\n",
" return\n",
" for i in range(len(data)-1):\n",
" swap(data, i, find_min_index(data, i))"
" return data"
]
},
{
@ -157,7 +154,7 @@
},
{
"cell_type": "code",
"execution_count": 3,
"execution_count": 2,
"metadata": {
"collapsed": false
},
@ -172,41 +169,35 @@
],
"source": [
"%%writefile test_selection_sort.py\n",
"from nose.tools import assert_equal\n",
"from nose.tools import assert_equal, assert_raises\n",
"\n",
"\n",
"class TestSelectionSort(object):\n",
"\n",
" def test_selection_sort(self, func):\n",
" print('None input')\n",
" data = None\n",
" func(data)\n",
" assert_equal(data, None)\n",
" assert_raises(TypeError, func, None)\n",
"\n",
" print('Empty input')\n",
" data = []\n",
" func(data)\n",
" assert_equal(data, [])\n",
" assert_equal(func([]), [])\n",
"\n",
" print('One element')\n",
" data = [5]\n",
" func(data)\n",
" assert_equal(data, [5])\n",
" assert_equal(func([5]), [5])\n",
"\n",
" print('Two or more elements')\n",
" data = [5, 1, 7, 2, 6, -3, 5, 7, -10]\n",
" func(data)\n",
" assert_equal(data, sorted(data))\n",
" assert_equal(func(data), sorted(data))\n",
"\n",
" print('Success: test_selection_sort\\n')\n",
"\n",
"\n",
"def main():\n",
" test = TestSelectionSort()\n",
" test.test_selection_sort(selection_sort)\n",
" selection_sort = SelectionSort()\n",
" test.test_selection_sort(selection_sort.sort)\n",
" try:\n",
" test.test_selection_sort(selection_sort_recursive)\n",
" test.test_selection_sort(selection_sort_iterative_alt)\n",
" test.test_selection_sort(selection_sort.sort_recursive)\n",
" test.test_selection_sort(selection_sort.sor_iterative_alt)\n",
" except NameError:\n",
" # Alternate solutions are only defined\n",
" # in the solutions file\n",
@ -219,7 +210,7 @@
},
{
"cell_type": "code",
"execution_count": 4,
"execution_count": 3,
"metadata": {
"collapsed": false
},
@ -237,15 +228,7 @@
"None input\n",
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n",
"None input\n",
"Empty input\n",
"One element\n",
"Two or more elements\n",
"Success: test_selection_sort\n",
"\n"
"Two or more elements\n"
]
}
],

24
sorting_searching/selection_sort/test_selection_sort.py
View File

@ -1,38 +1,32 @@
from nose.tools import assert_equal
from nose.tools import assert_equal, assert_raises
class TestSelectionSort(object):
def test_selection_sort(self, func):
print('None input')
data = None
func(data)
assert_equal(data, None)
assert_raises(TypeError, func, None)
print('Empty input')
data = []
func(data)
assert_equal(data, [])
assert_equal(func([]), [])
print('One element')
data = [5]
func(data)
assert_equal(data, [5])
assert_equal(func([5]), [5])
print('Two or more elements')
data = [5, 1, 7, 2, 6, -3, 5, 7, -10]
func(data)
assert_equal(data, sorted(data))
assert_equal(func(data), sorted(data))
print('Success: test_selection_sort\n')
def main():
test = TestSelectionSort()
test.test_selection_sort(selection_sort)
selection_sort = SelectionSort()
test.test_selection_sort(selection_sort.sort)
try:
test.test_selection_sort(selection_sort_recursive)
test.test_selection_sort(selection_sort_iterative_alt)
test.test_selection_sort(selection_sort.sort_recursive)
test.test_selection_sort(selection_sort.sor_iterative_alt)
except NameError:
# Alternate solutions are only defined
# in the solutions file