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https://github.com/donnemartin/interactive-coding-challenges.git
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Update selection sort challenge (#131)
Update constraints, test cases, code, and tests.
This commit is contained in:
Donne Martin
GitHub
parent
bb56b63c39
commit
daa7fba255
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@ -37,6 +37,10 @@
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"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
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" * Yes\n",
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"* Are duplicates allowed?\n",
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" * Yes\n",
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"* Can we assume the input is valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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]
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},
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@ -46,7 +50,7 @@
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"source": [
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"## Test Cases\n",
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"\n",
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"* None -> None\n",
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"* None -> Exception\n",
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"* Empty input -> []\n",
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"* One element -> [element]\n",
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"* Two or more elements"
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@ -76,22 +80,11 @@
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},
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"outputs": [],
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"source": [
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"def selection_sort(data, start=0):\n",
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" # TODO: Implement me (recursive)\n",
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" pass"
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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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"def selection_sort_iterative(data):\n",
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" # TODO: Implement me (iterative)\n",
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" pass"
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"class SelectionSort(object):\n",
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"\n",
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" def sort(self, data):\n",
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" # TODO: Implement me (recursive)\n",
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" pass"
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]
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},
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{
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@ -114,41 +107,35 @@
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"outputs": [],
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"source": [
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"# %load test_selection_sort.py\n",
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"from nose.tools import assert_equal\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestSelectionSort(object):\n",
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"\n",
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" def test_selection_sort(self, func):\n",
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" print('None input')\n",
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" data = None\n",
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" func(data)\n",
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" assert_equal(data, None)\n",
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" assert_raises(TypeError, func, None)\n",
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"\n",
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" print('Empty input')\n",
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" data = []\n",
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" func(data)\n",
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" assert_equal(data, [])\n",
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" assert_equal(func([]), [])\n",
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"\n",
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" print('One element')\n",
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" data = [5]\n",
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" func(data)\n",
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" assert_equal(data, [5])\n",
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" assert_equal(func([5]), [5])\n",
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"\n",
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" print('Two or more elements')\n",
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" data = [5, 1, 7, 2, 6, -3, 5, 7, -10]\n",
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" func(data)\n",
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" assert_equal(data, sorted(data))\n",
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" assert_equal(func(data), sorted(data))\n",
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"\n",
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" print('Success: test_selection_sort\\n')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestSelectionSort()\n",
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" test.test_selection_sort(selection_sort)\n",
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" selection_sort = SelectionSort()\n",
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" test.test_selection_sort(selection_sort.sort)\n",
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" try:\n",
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" test.test_selection_sort(selection_sort_recursive)\n",
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" test.test_selection_sort(selection_sort_iterative_alt)\n",
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" test.test_selection_sort(selection_sort.sort_recursive)\n",
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" test.test_selection_sort(selection_sort.sor_iterative_alt)\n",
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" except NameError:\n",
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" # Alternate solutions are only defined\n",
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" # in the solutions file\n",
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@ -36,6 +36,10 @@
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"* Is a naiive solution sufficient (ie not stable, not based on a heap)?\n",
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" * Yes\n",
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"* Are duplicates allowed?\n",
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" * Yes\n",
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"* Can we assume the input is valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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]
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},
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@ -45,7 +49,7 @@
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"source": [
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"## Test Cases\n",
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"\n",
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"* None -> None\n",
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"* None -> Exception\n",
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"* [] -> []\n",
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"* One element -> [element]\n",
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"* Two or more elements"
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@ -87,64 +91,57 @@
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},
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"outputs": [],
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"source": [
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"def selection_sort(data):\n",
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" if data is None or len(data) < 2:\n",
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" return\n",
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" for i in range(len(data)-1):\n",
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" min_index = i\n",
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" for j in range(i + 1, len(data)):\n",
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" if data[j] < data[min_index]:\n",
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" min_index = j\n",
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" data[i], data[min_index] = data[min_index], data[i]"
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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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"Below are alternate solutions with helper functions:"
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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": 2,
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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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"def find_min_index(data, start):\n",
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" # Raises an exception if: \n",
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" # -data is None\n",
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" # -start >= len(data) - 1\n",
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" min_index = start\n",
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" for i in range(start + 1, len(data)):\n",
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" if data[i] < data[min_index]:\n",
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"class SelectionSort(object):\n",
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"\n",
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" def sort(self, data):\n",
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" if data is None:\n",
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" raise TypeError('data cannot be None')\n",
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" if len(data) < 2:\n",
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" return data\n",
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" for i in range(len(data)-1):\n",
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" min_index = i\n",
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" return min_index\n",
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" for j in range(i+1, len(data)):\n",
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" if data[j] < data[min_index]:\n",
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" min_index = j\n",
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" if data[min_index] < data[i]:\n",
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" data[i], data[min_index] = data[min_index], data[i]\n",
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" return data\n",
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"\n",
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" def sort_iterative_alt(self, data):\n",
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" if data is None:\n",
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" raise TypeError('data cannot be None')\n",
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" if len(data) < 2:\n",
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" return data\n",
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" for i in range(len(data)-1):\n",
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" self._swap(data, i, self._find_min_index(data, i))\n",
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" return data\n",
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"\n",
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"def swap(data, i, j):\n",
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" # Raises an exception if: \n",
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" # -data is None\n",
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" # -i or j are >= len(data)\n",
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" if i != j:\n",
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" data[i], data[j] = data[j], data[i]\n",
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" def sort_recursive(self, data, start=0):\n",
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" if data is None:\n",
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" raise TypeError('data cannot be None')\n",
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" if len(data) < 2:\n",
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" return data\n",
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" return self._sort_recursive(data, start)\n",
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"\n",
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" def _sort_recursive(self, data, start):\n",
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" if data is None:\n",
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" return\n",
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" if start < len(data) - 1:\n",
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" swap(data, start, self._find_min_index(data, start))\n",
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" self._sort_recursive(data, start+1)\n",
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" return data\n",
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"\n",
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"def selection_sort_recursive(data, start=0):\n",
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" if data is None:\n",
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" return\n",
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" if start < len(data) - 1:\n",
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" swap(data, start, find_min_index(data, start))\n",
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" selection_sort_recursive(data, start+1)\n",
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" def _find_min_index(self, data, start):\n",
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" min_index = start\n",
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" for i in range(start+1, len(data)):\n",
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" if data[i] < data[min_index]:\n",
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" min_index = i\n",
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" return min_index\n",
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"\n",
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"\n",
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"def selection_sort_iterative_alt(data):\n",
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" if data is None or len(data) < 2:\n",
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" return\n",
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" for i in range(len(data)-1):\n",
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" swap(data, i, find_min_index(data, i))"
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" def _swap(self, data, i, j):\n",
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" if i != j:\n",
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" data[i], data[j] = data[j], data[i]\n",
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" return data"
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]
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},
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{
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@ -157,7 +154,7 @@
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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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"execution_count": 2,
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"metadata": {
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"collapsed": false
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},
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@ -172,41 +169,35 @@
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],
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"source": [
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"%%writefile test_selection_sort.py\n",
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"from nose.tools import assert_equal\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestSelectionSort(object):\n",
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"\n",
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" def test_selection_sort(self, func):\n",
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" print('None input')\n",
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" data = None\n",
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" func(data)\n",
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" assert_equal(data, None)\n",
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" assert_raises(TypeError, func, None)\n",
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"\n",
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" print('Empty input')\n",
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" data = []\n",
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" func(data)\n",
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" assert_equal(data, [])\n",
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" assert_equal(func([]), [])\n",
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"\n",
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" print('One element')\n",
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" data = [5]\n",
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" func(data)\n",
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" assert_equal(data, [5])\n",
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" assert_equal(func([5]), [5])\n",
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"\n",
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" print('Two or more elements')\n",
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" data = [5, 1, 7, 2, 6, -3, 5, 7, -10]\n",
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" func(data)\n",
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" assert_equal(data, sorted(data))\n",
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" assert_equal(func(data), sorted(data))\n",
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"\n",
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" print('Success: test_selection_sort\\n')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestSelectionSort()\n",
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" test.test_selection_sort(selection_sort)\n",
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" selection_sort = SelectionSort()\n",
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" test.test_selection_sort(selection_sort.sort)\n",
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" try:\n",
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" test.test_selection_sort(selection_sort_recursive)\n",
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" test.test_selection_sort(selection_sort_iterative_alt)\n",
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" test.test_selection_sort(selection_sort.sort_recursive)\n",
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" test.test_selection_sort(selection_sort.sor_iterative_alt)\n",
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" except NameError:\n",
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" # Alternate solutions are only defined\n",
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" # in the solutions file\n",
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@ -219,7 +210,7 @@
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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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"execution_count": 3,
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"metadata": {
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"collapsed": false
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},
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@ -237,15 +228,7 @@
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"None input\n",
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"Empty input\n",
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"One element\n",
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"Two or more elements\n",
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"Success: test_selection_sort\n",
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"\n",
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"None input\n",
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"Empty input\n",
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"One element\n",
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"Two or more elements\n",
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"Success: test_selection_sort\n",
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"\n"
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"Two or more elements\n"
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]
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}
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],
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@ -1,38 +1,32 @@
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from nose.tools import assert_equal
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from nose.tools import assert_equal, assert_raises
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class TestSelectionSort(object):
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def test_selection_sort(self, func):
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print('None input')
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data = None
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func(data)
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assert_equal(data, None)
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assert_raises(TypeError, func, None)
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print('Empty input')
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data = []
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func(data)
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assert_equal(data, [])
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assert_equal(func([]), [])
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print('One element')
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data = [5]
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func(data)
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assert_equal(data, [5])
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assert_equal(func([5]), [5])
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print('Two or more elements')
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data = [5, 1, 7, 2, 6, -3, 5, 7, -10]
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func(data)
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assert_equal(data, sorted(data))
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assert_equal(func(data), sorted(data))
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print('Success: test_selection_sort\n')
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def main():
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test = TestSelectionSort()
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test.test_selection_sort(selection_sort)
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selection_sort = SelectionSort()
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test.test_selection_sort(selection_sort.sort)
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try:
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test.test_selection_sort(selection_sort_recursive)
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test.test_selection_sort(selection_sort_iterative_alt)
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test.test_selection_sort(selection_sort.sort_recursive)
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test.test_selection_sort(selection_sort.sor_iterative_alt)
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except NameError:
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# Alternate solutions are only defined
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# in the solutions file
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