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Reworked notebook: Added more detail to constraints and test cases. Reworked unit test. Added linebreak to comment about naming clash with queue.

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Donne Martin 2015-06-27 06:36:52 -04:00
parent dd0e94fdd1
commit 0c43a34ae1
2 changed files with 76 additions and 24 deletions
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97
stacks-queues/queue-list.ipynb
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@ -13,10 +13,11 @@
"source": [ "source": [
"## Problem: Implement a queue with enqueue and dequeue methods using a linked list.\n", "## Problem: Implement a queue with enqueue and dequeue methods using a linked list.\n",
"\n", "\n",
"* [Clarifying Questions](#Clarifying-Questions)\n", "* [Constraints and Assumptions](#Constraints-and-Assumptions)\n",
"* [Test Cases](#Test-Cases)\n", "* [Test Cases](#Test-Cases)\n",
"* [Algorithm](#Algorithm)\n", "* [Algorithm](#Algorithm)\n",
"* [Code](#Code)\n", "* [Code](#Code)\n",
"* [Unit Test](#Unit-Test)\n",
"* [Pythonic-Code](#Pythonic-Code)" "* [Pythonic-Code](#Pythonic-Code)"
] ]
}, },
@ -24,7 +25,9 @@
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
"source": [ "source": [
"## Clarifying Questions\n", "## Constraints and Assumptions\n",
"\n",
"*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
"\n", "\n",
"* If there is one item in the list, do you expect the first and last pointers to both point to it?\n", "* If there is one item in the list, do you expect the first and last pointers to both point to it?\n",
" * Yes\n", " * Yes\n",
@ -91,14 +94,23 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 1,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
"outputs": [], "outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Overwriting queue_list.py\n"
]
}
],
"source": [ "source": [
"%%writefile queue_list.py\n", "%%writefile queue_list.py\n",
"# Need to avoid naming this queue.py as it will conflict with IPython Notebook\n", "# Need to avoid naming this queue.py as it \n",
"# will conflict with IPython Notebook\n",
"\n", "\n",
"class Node(object):\n", "class Node(object):\n",
" def __init__(self, data):\n", " def __init__(self, data):\n",
@ -123,6 +135,7 @@
" # Empty list\n", " # Empty list\n",
" if self.first is None and self.last is None:\n", " if self.first is None and self.last is None:\n",
" return None\n", " return None\n",
" \n",
" # Remove only element from a one element list\n", " # Remove only element from a one element list\n",
" elif self.first == self.last:\n", " elif self.first == self.last:\n",
" data = self.first.data\n", " data = self.first.data\n",
@ -137,7 +150,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 2,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
@ -146,29 +159,67 @@
"%run queue_list.py" "%run queue_list.py"
] ]
}, },
{
"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.*"
]
},
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 3,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
"outputs": [], "outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Test: Dequeue an empty queue\n",
"Test: Enqueue to an empty queue\n",
"Test: Dequeue a queue with one element\n",
"Test: Enqueue to a non-empty queue\n",
"Test: Dequeue a queue with more than one element\n",
"Success: test_end_to_end\n"
]
}
],
"source": [ "source": [
"print('Dequeue an empty queue')\n", "from nose.tools import assert_equal\n",
"queue = Queue()\n", "\n",
"print(queue.dequeue())\n", "class Test(object):\n",
"print('Enqueue to an empty queue')\n", " # TODO: It would be better if we had unit tests for each\n",
"queue.enqueue(1)\n", " # method in addition to the following end-to-end test\n",
"print('Dequeue a queue with one element')\n", " def test_end_to_end(self):\n",
"print(queue.dequeue())\n", " print('Test: Dequeue an empty queue')\n",
"print('Enqueue to a non-empty queue')\n", " queue = Queue()\n",
"queue.enqueue(2)\n", " assert_equal(queue.dequeue(), None)\n",
"queue.enqueue(3)\n", "\n",
"queue.enqueue(4)\n", " print('Test: Enqueue to an empty queue')\n",
"print('Dequeue a queue with more than one element')\n", " queue.enqueue(1)\n",
"print(queue.dequeue())\n", "\n",
"print(queue.dequeue())\n", " print('Test: Dequeue a queue with one element')\n",
"print(queue.dequeue())" " assert_equal(queue.dequeue(), 1)\n",
"\n",
" print('Test: Enqueue to a non-empty queue')\n",
" queue.enqueue(2)\n",
" queue.enqueue(3)\n",
" queue.enqueue(4)\n",
"\n",
" print('Test: Dequeue a queue with more than one element')\n",
" assert_equal(queue.dequeue(), 2)\n",
" assert_equal(queue.dequeue(), 3)\n",
" assert_equal(queue.dequeue(), 4)\n",
" \n",
" print('Success: test_end_to_end')\n",
"\n",
"if __name__ == '__main__':\n",
" test = Test()\n",
" test.test_end_to_end()"
] ]
}, },
{ {

3
stacks-queues/queue_list.py
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@ -1,4 +1,5 @@
# Need to avoid naming this queue.py as it will conflict with IPython Notebook # Need to avoid naming this queue.py as it
# will conflict with IPython Notebook
class Node(object): class Node(object):
def __init__(self, data): def __init__(self, data):