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Added remove duplicates challenge.

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Donne Martin
2015-07-02 23:11:54 -04:00
parent c16f25e5f3
commit d253a4929a
4 changed files with 310 additions and 77 deletions
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153
linked_lists/remove_duplicates/remove_duplicates_solution.ipynb
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@@ -4,7 +4,14 @@
"cell_type": "markdown",
"metadata": {},
"source": [
"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes).</i></small>"
"<small><i>This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges).</i></small>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Solution Notebook"
]
},
{
@@ -16,9 +23,8 @@
"* [Constraints](#Constraints)\n",
"* [Test Cases](#Test-Cases)\n",
"* [Algorithm: Hash Map Lookup](#Algorithm:-Hash-Map-Lookup)\n",
"* [Code: Hash Map Lookup](#Code:-Hash-Map-Lookup)\n",
"* [Algorithm: In-Place](#Algorithm:-In-Place)\n",
"* [Code: In-Place](#Code:-In-Place)\n",
"* [Code](#Code)\n",
"* [Unit Test](#Unit-Test)"
]
},
@@ -28,7 +34,7 @@
"source": [
"## Constraints\n",
"\n",
"*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
"*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
"\n",
"* Is this a singly or doubly linked list?\n",
" * Singly\n",
@@ -46,11 +52,10 @@
"source": [
"## Test Cases\n",
"\n",
"* Empty linked list\n",
"* One element linked list\n",
"* Multiple elements\n",
"* No duplicates\n",
"* One or more duplicates"
"* Empty linked list -> []\n",
"* One element linked list -> [element]\n",
"* General case with no duplicates\n",
"* General case with duplicates"
]
},
{
@@ -73,46 +78,6 @@
"* Deletion requires two pointers, one to the previous node and one to the current node"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Code: Hash Map Lookup"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"%run linked_list.py"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [],
"source": [
"class MyLinkedList(LinkedList):\n",
" def remove_dupes(self):\n",
" seen_data = set()\n",
" curr = self.head\n",
" prev = None\n",
" while curr is not None:\n",
" if curr.data in seen_data:\n",
" prev.next = curr.next\n",
" else:\n",
" seen_data.add(curr.data)\n",
" prev = curr\n",
" curr = curr.next"
]
},
{
"cell_type": "markdown",
"metadata": {},
@@ -139,19 +104,43 @@
"cell_type": "markdown",
"metadata": {},
"source": [
"## Code: In-Place"
"## Code"
]
},
{
"cell_type": "code",
"execution_count": 3,
"execution_count": 1,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": [
"%run ../linked_list/linked_list.py"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [],
"source": [
"class MyLinkedListAlt(LinkedList):\n",
"class MyLinkedList(LinkedList):\n",
" \n",
" def remove_dupes(self):\n",
" seen_data = set()\n",
" curr = self.head\n",
" prev = None\n",
" while curr is not None:\n",
" if curr.data in seen_data:\n",
" prev.next = curr.next\n",
" else:\n",
" seen_data.add(curr.data)\n",
" prev = curr\n",
" curr = curr.next\n",
" \n",
" def remove_dupes_in_place(self):\n",
" curr = self.head\n",
" while curr is not None:\n",
" runner = curr\n",
@@ -170,16 +159,9 @@
"## Unit Test"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"*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",
"execution_count": 4,
"execution_count": 3,
"metadata": {
"collapsed": false
},
@@ -188,25 +170,17 @@
"name": "stdout",
"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"
"Overwriting test_remove_duplicates.py\n"
]
}
],
"source": [
"%%writefile test_remove_duplicates.py\n",
"from nose.tools import assert_equal\n",
"\n",
"class Test(object):\n",
"\n",
"class TestRemoveDupes(object):\n",
" \n",
" def test_remove_dupes(self, linked_list):\n",
" print('Test: Empty list')\n",
" linked_list.remove_dupes()\n",
@@ -231,12 +205,37 @@
" \n",
" print('Success: test_remove_dupes\\n')\n",
"\n",
"if __name__ == '__main__':\n",
" test = Test()\n",
"def main():\n",
" test = TestRemoveDupes()\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)"
" \n",
"if __name__ == '__main__':\n",
" main()"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"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"
]
}
],
"source": [
"run -i test_remove_duplicates.py"
]
}
],