A graph can refer to a graphic (such as a chart or diagram) showing or displaying the relationship between two or more variables used, for instance, in visualizing scientific data.

learn more… | top users | synonyms

6
votes
1answer
108 views

Finding all paths from a given graph

I need to find all paths from a given graph. I can do that for now, however my recursive code is not efficient and my graphs are very complicated, hence I need a better algorithm. ...
6
votes
1answer
51 views

Extracting nodes from a road network

My code takes 143.023 seconds for extracting nodes from a road network of city like Göteborg in Sweden. Please check it out if I can optimize it. ...
4
votes
0answers
57 views

Thinking in 'Haskell' - when to use (state) Monads

I really enjoy Haskell but feel I still have a total beginner's style, and would like to move beyond that. The code below - for Dijkstra's shortest path algorithm - is a case in point. I feel as ...
5
votes
1answer
54 views

Generic Graph Library Part 2 : Algorithms

(This is a follow on to this question). Having given an implementation for some of the graph structures, here is a portion of the algorithms that are defined to work over them: graph_degree.hpp ...
9
votes
1answer
83 views

Generic Graph Library

I've been working on a generic graph library for a while now, in a bit of an off and on fashion. I realise that boost::graph exists, but it is a complex library ...
3
votes
2answers
82 views

Simplify an if else construct with assignment before if and else

I want to simplify an if: .. else: .. construct: ...
2
votes
1answer
49 views

M coloring problem

Given an undirected graph and a number m, determine if the graph can be colored with at most m colors such that no two adjacent vertices of the graph are colored with same color. Here coloring of a ...
0
votes
2answers
64 views

Detect cycle in an undirected graph

This code detects cycle in acyclic graph. The assumption of this approach is that there are no parallel edges between any two vertices. Looking for code review, best practices and optimizations. ...
1
vote
0answers
23 views

plotting many images at once in matplotlib

I am using numpy and matplotlib to do a statistical simulation. The simulation itself is pretty fast thanks to numPy vectorizatio, however the plotting is slow since I still use a for loop. Here is ...
4
votes
1answer
55 views

JFreeChart Dynamic Scatter Chart

I have a model that consists of a 100 'agents' that change their x and y coordinates randomly. I use JFreeChart scatter chart to represent agents' locations. ...
7
votes
2answers
228 views

Missing level of technical depth (Common Ancestor)

I recently have given a coding test in a reputable IT company. There were three coding questions. They refused me by saying that as we felt they didn't demonstrate the level of technical depth ...
6
votes
1answer
133 views

Escaping the prison - finding the shortest way

I have given an assignment where I have to escape a labyrinth. The goal is to find the shortest way. I have done some research and there seem to be two strategies to solve the problem: the Depth-first ...
7
votes
3answers
373 views

Depth First Traversal of a Graph

I am learning how to implement a basic undirected graph and perform a depth first traversal. Please critique my code for correctness, best practices, security, and any other comments that may be ...
1
vote
0answers
42 views

How to design a user defined graph structure?

First, my code to review: ...
2
votes
4answers
2k views

Depth First Search & Breadth First Search implementation

I've implemented DFS and BFS implementations. I want to check if the code is readable, contains any issues, and can be improved. GraphImplementation ...
3
votes
1answer
162 views

Tarjan's algorithm for Strongly Connected Components without keeping SCC in stack

I've been looking for an implementation of Tarjan's algorithm in C#/C++ for a strongly-connected components in graphs, and couldn't find any implementation without use of additional Stack - most of ...
2
votes
1answer
74 views

Lift ball which leads to shortest height

There are n balls kept on a table and connected by same singe connected string (which can be cyclic or maynot). Write the code to select a ball such that after lifting the whole structure from that ...
5
votes
1answer
69 views

Strongly connected components algorithm

In my Python application, I am using Tarjan's algorithm to compute strongly connected components. Unfortunately, it shows up under profiling as one of the top functions in my application (at least ...
6
votes
2answers
125 views

Clone of an undirected graph

Perform a graph clone. Verifying complexity to be O(E). Looking for code review, optimizations and best practices. ...
3
votes
1answer
69 views

Clone an undirected graph

I'm looking for code-review, optimization and best practices. Also verifying complexity to be O(E) time and O(V+E) space complexity. ...
6
votes
2answers
544 views

Ford-Fulkerson algorithm

Solved the ford-fulkerson algorithm, which is too vast to explain it comprehensively here. Check Wikipedia for Ford-Fulkerson and Princeton lecture on Ford-Fulkerson. Looking for code review, ...
11
votes
3answers
1k views

Find all paths from source to destination

Given a directed connected graphs, find all paths from source to destination. Looking for code review, optimizations and best practices. Also need help figuring out complexity, which in my best ...
2
votes
0answers
19 views

Completing a Graph in Scheme

For the record, this is part of a homework assignment, but I have already implemented a solution. I am simply wondering if there is a better way to do it. Background: I am asked to write a procedure, ...
11
votes
1answer
1k views

Topological sort in Java

I am learning algorithms in graphs. I have implemented topological sort using Java. Kindly review my code and provide me with feedback. ...
0
votes
0answers
55 views

Iterative DFS algorithm

I've written an iterative version for DFS. For a quick overview of the benchmark results for a complete graph: So it looks like it behaves within the boundaries of the theoretical complexity. ...
5
votes
2answers
212 views

Constraint Programming: Map color problem

I've written some python code to solve the map coloring problem. In my code, I represent the problem using Territory and ...
6
votes
1answer
142 views

Dijkstra-like routing algorithm

I've got the following code to find the shortest path between two nodes using almost-Dijkstra's-algorithm which was written for an exercise, and I'm looking for things to improve my general Scala ...
4
votes
1answer
54 views

Maximize the number of nodes that could be reachable in a graph

Description of my code: I am trying to maximize the number of nodes that could be reachable in a graph. Please do not consider my main algorithm, I want it to be like that. The only parts that I need ...
4
votes
1answer
112 views

Modified BFS code optimizations

I need some help reviewing this code in terms of making as fast as possible. This is a modified version of BFS that does quite a bit of processing on the side. Use case: I have a large graph ...
1
vote
0answers
66 views

Actionscript Graph data structure implementation

So, I am not sure if I should have Vertex extend Point, because the equals() and ...
2
votes
1answer
172 views

Automate a dependency graph with parallel programming [closed]

I found a C/Linux exercise in a book, and I propose a code as a solution, please feel free to correct it. Here is the exercise : Taking into consideration the following dependency graph, which ...
4
votes
1answer
315 views

Dijkstra's and Prim's algorithms: correctness/efficiency

This is in preparation for a competition that only allows C++03. ...
5
votes
1answer
182 views

Code to construct a complete graph

I have tried to design a class for a complete graph. Needless to say, disadvantages of my current solution are very visible: dependent inputs have led to verification headaches. In this code we ...
9
votes
2answers
3k views

A* search algorithm

NodeData stores all information of the node needed by the AStar algorithm. This information includes the value of ...
7
votes
2answers
1k views

Check if directed graph contains a cycle

I have solved the question, and in turn felt the need to get it reviewed. Any suggestions for clean up and optimization would help. Also please verify my complexity: \$O(V + E)\$. ...
3
votes
0answers
302 views

STL and Dijkstra's algorithm optimization

This is the problem and my solution to this is: ...
5
votes
1answer
2k views

Prims algorithm implementation

Review this code regarding optimization, cleanup, and best practices. ...
5
votes
2answers
6k views

Learning to code a graph

This is my first attempt at putting the conceptual knowledge I've gained about graphs into code. When searching for examples they all seem overly complicated, and searching for a tutorial or ...
5
votes
2answers
147 views

How to improve this algorithm for building a graphs closures

We have a large directed acyclic graph and a requirement to filter it by allowing a user to select certain nodes and then we remove all nodes that are not selected nodes, ancestors of those nodes, or ...
0
votes
1answer
118 views

Applying Dijkastra's algorithm on a graph of five nodes

Last week I posted a piece of code to apply Dijkastra algorithm to calculate the shortest path between to nodes in a graph. Now, I've made some improvements, but I am still having difficulties. I ...
2
votes
1answer
3k views

Implementation of Prim's minimum spanning tree

Feel free to tell about every possible issue (style, errors, inffective solution etc.) you found. Here is the main part of what I want to be reviewed, through there is some related code on GitHub. ...
2
votes
0answers
115 views

Evaluating code for a graph [closed]

This is relatively long code. Please take a look at this code if you are still willing to do so. I will appreciate your feedback. I have spent two days trying to come up with code to represent a ...
1
vote
1answer
187 views

DFS algorithm with generators

Background: I was working on a project were I needed to write some rules for text-processing. After working on this project for a couple of days and implementing some rules, I realized I needed to ...
3
votes
1answer
100 views

Review/rate my new graph class

I have written a PHP class called "graph". It is a class that performs RESTful-like commands to a MySQL database. I have posted the GitHub repo. Here is the code as well: config.php ...
5
votes
2answers
2k views

Implementation of Dijkstra's algorithm

Please pick my code apart and give me some feedback on how I could make it better or more simple. ...
1
vote
1answer
163 views

2003 Canadian Computing Competition, Stage 1 ; Why Is My Solution Invalid?

I am doing old versions of the Canadian Computing Competition, on a website where I can run my solution against some test cases they have. I am failing one of their test cases, and cannot figure out ...
6
votes
1answer
245 views

Shortest Path in a Unit Cost DAG BFS in Hadoop

Just got done implementing a shortest path algo of a unit cost DAG BFS in Hadoop and wanting to get anyone's opinion on how I could have done it better. The main issue I see is that I lose the ...
4
votes
1answer
709 views

Do I need to delete a vector?

I want to make a graph from input from a text file in the format: vertex1 vertex2 cost time where vertex1 and vertex2 are strings that form an edge and cost and ...
3
votes
1answer
261 views

Please review my Digraph Code in Java

can people please review my digraph code? This is used to create a directed graph of type T. The directed graph has edges and vertices with values but is directional such that nodes can loop unto ...
4
votes
1answer
593 views

BFS and DFS in Scala

I would love it if someone could give me some suggestions for these 2 graph search functions. I am new to scala and would love to get some insight into making these more idiomatic. ...