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Reworked notebook: Added more detail to constraints and test cases. Reworked code and unit test.

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Donne Martin 2015-06-27 06:40:29 -04:00
parent 0ca2b20da1
commit dd79e20c4b
1 changed files with 78 additions and 34 deletions
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112
recursion-dynamic/fibonacci.ipynb
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@ -13,18 +13,22 @@
"source": [ "source": [
"## Problem: Implement fibonacci recursively, dynamically, and iteratively.\n", "## Problem: Implement fibonacci recursively, dynamically, and iteratively.\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: Recursive](#Code:-Recursive)\n",
"* [Pythonic-Code](#Pythonic-Code)" "* [Code: Dynamic](#Code:-Dynamic)\n",
"* [Code: Iterative](#Code:-Iterative)\n",
"* [Unit Test](#Unit-Test)"
] ]
}, },
{ {
"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",
"* None" "* None"
] ]
@ -59,23 +63,12 @@
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
"source": [ "source": [
"## Code" "## Code: Recursive"
] ]
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 1,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"num_items = 10"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
@ -85,20 +78,25 @@
" if n == 0 or n == 1:\n", " if n == 0 or n == 1:\n",
" return n\n", " return n\n",
" else:\n", " else:\n",
" return fib_recursive(n-1) + fib_recursive(n-2)\n", " return fib_recursive(n-1) + fib_recursive(n-2)"
"\n", ]
"for i in xrange(num_items):\n", },
" print(fib_recursive(i))" {
"cell_type": "markdown",
"metadata": {},
"source": [
"## Code: Dynamic"
] ]
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 2,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
"outputs": [], "outputs": [],
"source": [ "source": [
"num_items = 10\n",
"cache = [None] * (num_items + 1)\n", "cache = [None] * (num_items + 1)\n",
"\n", "\n",
"def fib_dynamic(n):\n", "def fib_dynamic(n):\n",
@ -107,29 +105,75 @@
" if cache[n] != None:\n", " if cache[n] != None:\n",
" return cache[n]\n", " return cache[n]\n",
" cache[n] = fib_dynamic(n-1) + fib_dynamic(n-2)\n", " cache[n] = fib_dynamic(n-1) + fib_dynamic(n-2)\n",
" return cache[n]\n", " return cache[n]"
"\n", ]
"for i in xrange(num_items):\n", },
" print(fib_dynamic(i))" {
"cell_type": "markdown",
"metadata": {},
"source": [
"## Code: Iterative"
] ]
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 3,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
"outputs": [], "outputs": [],
"source": [ "source": [
"def fib_iterative(n):\n", "def fib_iterative(n):\n",
" a = 0 \n", " a = 0 \n",
" b = 1\n", " b = 1\n",
" for _ in xrange(n):\n", " for _ in xrange(n):\n",
" a, b = b, a + b\n", " a, b = b, a + b\n",
" return a\n", " return a"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Unit Test\n",
"\n", "\n",
"for i in xrange(num_items):\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.*"
" print(fib_iterative(i))" ]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Success: test_fib\n",
"Success: test_fib\n",
"Success: test_fib\n"
]
}
],
"source": [
"from nose.tools import assert_equal\n",
"\n",
"class Test(object):\n",
" def test_fib(self, func):\n",
" result = []\n",
" for i in xrange(num_items):\n",
" result.append(func(i))\n",
" fib_seq = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]\n",
" assert_equal(result, fib_seq)\n",
" print('Success: test_fib')\n",
"\n",
"if __name__ == '__main__':\n",
" test = Test()\n",
" test.test_fib(fib_recursive)\n",
" test.test_fib(fib_dynamic)\n",
" test.test_fib(fib_iterative)"
] ]
} }
], ],