mirror of
https://github.com/donnemartin/interactive-coding-challenges
synced 2026-01-06 17:38:02 +00:00
Added basic graph implementation challenge.
This commit is contained in:
Donne Martin
252
graphs_trees/graph/graph_solution.ipynb
Normal file
252
graphs_trees/graph/graph_solution.ipynb
Normal file
@@ -0,0 +1,252 @@
|
||||
{
|
||||
"cells": [
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"<small><i>This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"# Solution Notebook"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Problem: Implement a basic graph.\n",
|
||||
"\n",
|
||||
"* [Constraints](#Constraints)\n",
|
||||
"* [Test Cases](#Test-Cases)\n",
|
||||
"* [Algorithm](#Algorithm)\n",
|
||||
"* [Code](#Code)\n",
|
||||
"* [Unit Test](#Unit-Test)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Constraints\n",
|
||||
"\n",
|
||||
"* I plan to use a Node and Graph class. \n",
|
||||
" * Node will keep track of its id, visit state, and connections. \n",
|
||||
" * Connections will be a dictionary with the key = node id and value being the edge weight\n",
|
||||
" * Graph will hold all of the nodes and have functions to add nodes and edges. \n",
|
||||
" * Is this in line with what you have in mind?\n",
|
||||
" * Yes"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Test Cases\n",
|
||||
"\n",
|
||||
"Input:\n",
|
||||
"* `add_edge(source, destination, weight)`\n",
|
||||
"\n",
|
||||
"```\n",
|
||||
"graph.add_edge(0, 1, 5)\n",
|
||||
"graph.add_edge(0, 5, 2)\n",
|
||||
"graph.add_edge(1, 2, 3)\n",
|
||||
"graph.add_edge(2, 3, 4)\n",
|
||||
"graph.add_edge(3, 4, 5)\n",
|
||||
"graph.add_edge(3, 5, 6)\n",
|
||||
"graph.add_edge(4, 0, 7)\n",
|
||||
"graph.add_edge(5, 4, 8)\n",
|
||||
"graph.add_edge(5, 2, 9)\n",
|
||||
"```\n",
|
||||
"\n",
|
||||
"Result:\n",
|
||||
"* `source` and `destination` nodes within `graph` are connected with specified `weight`."
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Algorithm\n",
|
||||
"\n",
|
||||
"### add_node\n",
|
||||
"\n",
|
||||
"* Create a node with the input id\n",
|
||||
"* Add the newly created node to the list of nodes\n",
|
||||
"\n",
|
||||
"Complexity:\n",
|
||||
"* Time: O(1)\n",
|
||||
"* Space: O(1)\n",
|
||||
"\n",
|
||||
"### add_edge\n",
|
||||
"\n",
|
||||
"* If the source node is not in the list of nodes, add it\n",
|
||||
"* If the dest node is not in the list of nodes, add it\n",
|
||||
"* Add a connection from the source node to the dest node with the given edge weight\n",
|
||||
"\n",
|
||||
"Complexity:\n",
|
||||
"* Time: O(1)\n",
|
||||
"* Space: O(1)"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Code"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 1,
|
||||
"metadata": {
|
||||
"collapsed": true
|
||||
},
|
||||
"outputs": [],
|
||||
"source": [
|
||||
"# Python 2 users: Run pip install enum34\n",
|
||||
"from enum import Enum\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"class State(Enum):\n",
|
||||
" unvisited = 1\n",
|
||||
" visited = 2\n",
|
||||
" visiting = 3\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"class Node:\n",
|
||||
"\n",
|
||||
" def __init__(self, id):\n",
|
||||
" self.id = id\n",
|
||||
" self.state = State.unvisited\n",
|
||||
" self.connections = {}\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"class Graph:\n",
|
||||
"\n",
|
||||
" def __init__(self):\n",
|
||||
" self.nodes = {}\n",
|
||||
"\n",
|
||||
" def add_node(self, id):\n",
|
||||
" node = Node(id)\n",
|
||||
" self.nodes[id] = node\n",
|
||||
" return node\n",
|
||||
"\n",
|
||||
" def add_edge(self, source, dest, weight=0):\n",
|
||||
" if source not in self.nodes:\n",
|
||||
" self.add_node(source)\n",
|
||||
" if dest not in self.nodes:\n",
|
||||
" self.add_node(dest)\n",
|
||||
" self.nodes[source].connections[self.nodes[dest]] = weight"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "markdown",
|
||||
"metadata": {},
|
||||
"source": [
|
||||
"## Unit Test"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 2,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"Overwriting test_graph.py\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"%%writefile test_graph.py\n",
|
||||
"from nose.tools import assert_equal\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"class TestGraph(object):\n",
|
||||
"\n",
|
||||
" def test_graph(self):\n",
|
||||
" graph = Graph()\n",
|
||||
" for key in range(0, 6):\n",
|
||||
" graph.add_node(key)\n",
|
||||
" graph.add_edge(0, 1, 5)\n",
|
||||
" graph.add_edge(0, 5, 2)\n",
|
||||
" graph.add_edge(1, 2, 3)\n",
|
||||
" graph.add_edge(2, 3, 4)\n",
|
||||
" graph.add_edge(3, 4, 5)\n",
|
||||
" graph.add_edge(3, 5, 6)\n",
|
||||
" graph.add_edge(4, 0, 7)\n",
|
||||
" graph.add_edge(5, 4, 8)\n",
|
||||
" graph.add_edge(5, 2, 9)\n",
|
||||
"\n",
|
||||
" assert_equal(graph.nodes[0].connections[graph.nodes[1]], 5)\n",
|
||||
" assert_equal(graph.nodes[0].connections[graph.nodes[5]], 2)\n",
|
||||
" assert_equal(graph.nodes[1].connections[graph.nodes[2]], 3)\n",
|
||||
" assert_equal(graph.nodes[2].connections[graph.nodes[3]], 4)\n",
|
||||
" assert_equal(graph.nodes[3].connections[graph.nodes[4]], 5)\n",
|
||||
" assert_equal(graph.nodes[3].connections[graph.nodes[5]], 6)\n",
|
||||
" assert_equal(graph.nodes[4].connections[graph.nodes[0]], 7)\n",
|
||||
" assert_equal(graph.nodes[5].connections[graph.nodes[4]], 8)\n",
|
||||
" assert_equal(graph.nodes[5].connections[graph.nodes[2]], 9)\n",
|
||||
"\n",
|
||||
" print('Success: test_graph')\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"def main():\n",
|
||||
" test = TestGraph()\n",
|
||||
" test.test_graph()\n",
|
||||
"\n",
|
||||
"\n",
|
||||
"if __name__ == '__main__':\n",
|
||||
" main()"
|
||||
]
|
||||
},
|
||||
{
|
||||
"cell_type": "code",
|
||||
"execution_count": 3,
|
||||
"metadata": {
|
||||
"collapsed": false
|
||||
},
|
||||
"outputs": [
|
||||
{
|
||||
"name": "stdout",
|
||||
"output_type": "stream",
|
||||
"text": [
|
||||
"Success: test_graph\n"
|
||||
]
|
||||
}
|
||||
],
|
||||
"source": [
|
||||
"%run -i test_graph.py"
|
||||
]
|
||||
}
|
||||
],
|
||||
"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": "2.7.10"
|
||||
}
|
||||
},
|
||||
"nbformat": 4,
|
||||
"nbformat_minor": 0
|
||||
}
|
||||
Reference in New Issue
Block a user