mirror of
https://github.com/donnemartin/interactive-coding-challenges.git
synced 2024-03-22 13:11:13 +08:00
Added notebook solving the following: Partition a linked list around a given value.
This commit is contained in:
Donne Martin
parent
4c1f87a2ae
commit
24525d5684
|
|
@ -18,6 +18,7 @@ Continually updated IPython Notebooks containing algorithms and data structures.
|
|||
* [Remove duplicates from a linked list](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/linked-lists/remove-duplicates.ipynb)
|
||||
* [Find the kth to last element of a linked list](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/linked-lists/kth-to-last-elem.ipynb)
|
||||
* [Delete a node in the middle of a linked list, given access to only that node](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/linked-lists/delete-mid.ipynb)
|
||||
* [Partition a linked list around a given value](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/linked-lists/partition.ipynb)
|
||||
|
||||
## License
|
||||
|
||||
|
|
|
|||
178
linked-lists/partition.ipynb
Normal file
178
linked-lists/partition.ipynb
Normal file
|
|
@ -0,0 +1,178 @@
|
|||
{
|
||||
"cells": [
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Problem: Partition a linked list around a value x, such that all nodes less than x come before all nodes greater than or equal to x.\n",
|
||||
"\n",
|
||||
"* [Clarifying Questions](#Clarifying-Questions)\n",
|
||||
"* [Test Cases](#Test-Cases)\n",
|
||||
"* [Algorithm](#Algorithm)\n",
|
||||
"* [Code](#Code)\n",
|
||||
"* [Pythonic-Code](#Pythonic-Code)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Clarifying Questions\n",
|
||||
"\n",
|
||||
"* Can we create additional data structures?\n",
|
||||
" * Yes\n",
|
||||
"* Do you expect the function to return a new list?\n",
|
||||
" * Yes"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Test Cases\n",
|
||||
"\n",
|
||||
"* Empty list\n",
|
||||
"* One element list\n",
|
||||
"* Left linked list is empty\n",
|
||||
"* Right linked list is empty\n",
|
||||
"* X invalid\n",
|
||||
"* General case\n",
|
||||
" * Partition = 10\n",
|
||||
" * Input: 4, 3, 7, 8, 10, 1, 10, 12\n",
|
||||
" * Output: 4, 3, 7, 8, 1, 10, 10, 12"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Algorithm\n",
|
||||
"\n",
|
||||
"* Test error cases\n",
|
||||
"* Create left and right linked lists\n",
|
||||
"* For each element in the list\n",
|
||||
" * If elem < x, append to the left list\n",
|
||||
" * else, append to the right list\n",
|
||||
"* Merge left and right lists\n",
|
||||
"\n",
|
||||
"Complexity:\n",
|
||||
"* Time: O(n)\n",
|
||||
"* Space: O(n)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Code"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": null,
|
||||
"metadata": {
|
||||
"collapsed": true
|
||||
},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"%run linked_list.py"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": null,
|
||||
"metadata": {
|
||||
"collapsed": true
|
||||
},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"class MyLinkedList(LinkedList):\n",
|
||||
" def partition(self, data):\n",
|
||||
" if self.head is None:\n",
|
||||
" return\n",
|
||||
" if type(data) != int:\n",
|
||||
" raise ValueError('Invalid int argument: data')\n",
|
||||
" left = MyLinkedList(None)\n",
|
||||
" right = MyLinkedList(None)\n",
|
||||
" curr = self.head\n",
|
||||
" while curr is not None:\n",
|
||||
" if curr.data < data:\n",
|
||||
" left.append(curr.data)\n",
|
||||
" else:\n",
|
||||
" right.append(curr.data)\n",
|
||||
" curr = curr.next\n",
|
||||
" curr_left = left.head\n",
|
||||
" if curr_left is None:\n",
|
||||
" return right\n",
|
||||
" else:\n",
|
||||
" while curr_left.next is not None:\n",
|
||||
" curr_left = curr_left.next\n",
|
||||
" curr_left.next = right.head\n",
|
||||
" return left"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": null,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"print('Empty list')\n",
|
||||
"linked_list = MyLinkedList(None)\n",
|
||||
"linked_list.partition(10)\n",
|
||||
"linked_list.print_list()\n",
|
||||
"print('X invalid')\n",
|
||||
"head = Node(12)\n",
|
||||
"linked_list = MyLinkedList(head)\n",
|
||||
"try:\n",
|
||||
" linked_list.partition('a')\n",
|
||||
"except ValueError as err:\n",
|
||||
" print(err)\n",
|
||||
"linked_list.print_list()\n",
|
||||
"print('One element list')\n",
|
||||
"print('Left linked list is empty')\n",
|
||||
"linked_list.partition(1)\n",
|
||||
"linked_list.print_list()\n",
|
||||
"print('Right linked list is empty')\n",
|
||||
"linked_list.partition(20)\n",
|
||||
"linked_list.print_list()\n",
|
||||
"print('General case')\n",
|
||||
"# Partition = 10\n",
|
||||
"# Input 4, 3, 7, 8, 10, 1, 10, 12\n",
|
||||
"# Output 4, 3, 7, 8, 1, 10, 10, 12\n",
|
||||
"linked_list.insert_to_front(10)\n",
|
||||
"linked_list.insert_to_front(1)\n",
|
||||
"linked_list.insert_to_front(10)\n",
|
||||
"linked_list.insert_to_front(8)\n",
|
||||
"linked_list.insert_to_front(7)\n",
|
||||
"linked_list.insert_to_front(3)\n",
|
||||
"linked_list.insert_to_front(4)\n",
|
||||
"partitioned_list = linked_list.partition(10)\n",
|
||||
"partitioned_list.print_list()"
|
||||
]
|
||||
}
|
||||
],
|
||||
"metadata": {
|
||||
"kernelspec": {
|
||||
"display_name": "Python 2",
|
||||
"language": "python",
|
||||
"name": "python2"
|
||||
},
|
||||
"language_info": {
|
||||
"codemirror_mode": {
|
||||
"name": "ipython",
|
||||
"version": 2
|
||||
},
|
||||
"file_extension": ".py",
|
||||
"mimetype": "text/x-python",
|
||||
"name": "python",
|
||||
"nbconvert_exporter": "python",
|
||||
"pygments_lexer": "ipython2",
|
||||
"version": "2.7.9"
|
||||
}
|
||||
},
|
||||
"nbformat": 4,
|
||||
"nbformat_minor": 0
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user