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

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Donne Martin 2015-06-26 05:08:48 -04:00
parent b32affa79e
commit 9490979fe5
1 changed files with 85 additions and 65 deletions
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150
linked-lists/remove-duplicates.ipynb
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@ -13,26 +13,31 @@
"source": [ "source": [
"## Problem: Remove duplicates from a linked list\n", "## Problem: Remove duplicates from 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: Hash Map Lookup](#Algorithm:-Hash-Map-Lookup)\n", "* [Algorithm: Hash Map Lookup](#Algorithm:-Hash-Map-Lookup)\n",
"* [Code: Hash Map Lookup](#Code:-Hash-Map-Lookup)\n", "* [Code: Hash Map Lookup](#Code:-Hash-Map-Lookup)\n",
"* [Algorithm: In-Place](#Algorithm:-In-Place)\n", "* [Algorithm: In-Place](#Algorithm:-In-Place)\n",
"* [Code: In-Place](#Code:-In-Place)" "* [Code: In-Place](#Code:-In-Place)\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",
"* Is this a singly or doubly linked list?\n", "* Is this a singly or doubly linked list?\n",
" * Singly\n", " * Singly\n",
"* Can you insert NULL values in the list?\n", "* Can you insert NULL values in the list?\n",
" * No\n", " * No\n",
"* Can you use additional data structures?\n", "* Can you use additional data structures?\n",
" * Implement both solutions" " * Implement both solutions\n",
"* Can we assume we already have a linked list class that can be used for this problem?\n",
" * Yes"
] ]
}, },
{ {
@ -77,7 +82,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 1,
"metadata": { "metadata": {
"collapsed": true "collapsed": true
}, },
@ -88,7 +93,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 2,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
@ -108,36 +113,6 @@
" curr = curr.next" " curr = curr.next"
] ]
}, },
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": false
},
"outputs": [],
"source": [
"# Empty linked list\n",
"linked_list = MyLinkedList(None)\n",
"linked_list.remove_dupes()\n",
"linked_list.print_list()\n",
"# One element linked list\n",
"head = Node(2)\n",
"linked_list = MyLinkedList(head)\n",
"linked_list.remove_dupes()\n",
"linked_list.print_list()\n",
"# Multiple elements\n",
"# One or more duplicates\n",
"linked_list.insert_to_front(1)\n",
"linked_list.insert_to_front(3)\n",
"linked_list.insert_to_front(1)\n",
"linked_list.insert_to_front(1)\n",
"linked_list.remove_dupes()\n",
"linked_list.print_list()\n",
"# No duplicates\n",
"linked_list.remove_dupes()\n",
"linked_list.print_list()"
]
},
{ {
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
@ -169,14 +144,13 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": null, "execution_count": 3,
"metadata": { "metadata": {
"collapsed": false "collapsed": false
}, },
"outputs": [], "outputs": [],
"source": [ "source": [
"class MyLinkedList(LinkedList):\n", "class MyLinkedListAlt(LinkedList):\n",
" \n",
" def remove_dupes(self):\n", " def remove_dupes(self):\n",
" curr = self.head\n", " curr = self.head\n",
" while curr is not None:\n", " while curr is not None:\n",
@ -190,33 +164,79 @@
] ]
}, },
{ {
"cell_type": "code", "cell_type": "markdown",
"execution_count": null, "metadata": {},
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [ "source": [
"# Empty linked list\n", "## Unit Test"
"linked_list = MyLinkedList(None)\n", ]
"linked_list.remove_dupes()\n", },
"linked_list.print_list()\n", {
"# One element linked list\n", "cell_type": "markdown",
"head = Node(2)\n", "metadata": {},
"linked_list = MyLinkedList(head)\n", "source": [
"linked_list.remove_dupes()\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.*"
"linked_list.print_list()\n", ]
"# Multiple elements\n", },
"# One or more duplicates\n", {
"linked_list.insert_to_front(1)\n", "cell_type": "code",
"linked_list.insert_to_front(3)\n", "execution_count": 4,
"linked_list.insert_to_front(1)\n", "metadata": {
"linked_list.insert_to_front(1)\n", "collapsed": false
"linked_list.remove_dupes()\n", },
"linked_list.print_list()\n", "outputs": [
"# No duplicates\n", {
"linked_list.remove_dupes()\n", "name": "stdout",
"linked_list.print_list()" "output_type": "stream",
"text": [
"Test: Empty list\n",
"Test: One element list\n",
"Test: General case, duplicates\n",
"Test: General case, no duplicates\n",
"Success: test_remove_dupes\n",
"\n",
"Test: Empty list\n",
"Test: One element list\n",
"Test: General case, duplicates\n",
"Test: General case, no duplicates\n",
"Success: test_remove_dupes\n",
"\n"
]
}
],
"source": [
"from nose.tools import assert_equal\n",
"\n",
"class Test(object):\n",
" def test_remove_dupes(self, linked_list):\n",
" print('Test: Empty list')\n",
" linked_list.remove_dupes()\n",
" assert_equal(linked_list.get_all_data(), [])\n",
"\n",
" print('Test: One element list')\n",
" linked_list.insert_to_front(2)\n",
" linked_list.remove_dupes()\n",
" assert_equal(linked_list.get_all_data(), [2])\n",
"\n",
" print('Test: General case, duplicates')\n",
" linked_list.insert_to_front(1)\n",
" linked_list.insert_to_front(3)\n",
" linked_list.insert_to_front(1)\n",
" linked_list.insert_to_front(1)\n",
" linked_list.remove_dupes()\n",
" assert_equal(linked_list.get_all_data(), [1, 3, 2])\n",
"\n",
" print('Test: General case, no duplicates')\n",
" linked_list.remove_dupes()\n",
" assert_equal(linked_list.get_all_data(), [1, 3, 2])\n",
" \n",
" print('Success: test_remove_dupes\\n')\n",
"\n",
"if __name__ == '__main__':\n",
" test = Test()\n",
" linked_list = MyLinkedList(None)\n",
" test.test_remove_dupes(linked_list)\n",
" linked_list_alt = MyLinkedListAlt(None)\n",
" test.test_remove_dupes(linked_list_alt)"
] ]
} }
], ],