A graph is an abstract representation of objects (vertices) connected by links (edges). For questions about plotting data graphically, use the [data-visualization] tag instead.

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2
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1answer
45 views

Interview adjacency list graph problems in C++: proper graph implementation

I know this type of question has been asked before. However, my reason for asking it is gaining insight into what is expected in a 45 min interview when asked to implement graph algorithms. I have ...
2
votes
2answers
59 views

Parsing a text file of node data into Nodes and Edges

I'm a fairly new developer (well, engineer really, but currently working on a software project). In the Android project I'm working on, I read a node representation of a map into my app and interpret ...
5
votes
5answers
153 views

Enumeration of random trees

I'm interested in recursive generation of trees in Python. For my eventual application, it's important that the trees be represented as a list of nodes (rather than say a dictionary, or an edge list, ...
3
votes
1answer
73 views

Converting a CSV file to a social network graph for Pajek

The code will ask for a directory and will then read the CSV file and then generate a file in that directory describing a social network for Pajek. Does anyone know a way to load this CSV file to a ...
6
votes
1answer
66 views

Topological sort

The algorithm works in steps: Produce the graph in the form of an adjacency list e.g. this graph 0 - - 2 \ 1 -- 3 produces this adjacency list ...
3
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0answers
27 views

Golang A* Pathfinder

This is a generalized A* pathfinder in Go. I am new to the language and am eager for advice about best practices. In particular, I am not sure if the type assertion I make in ...
2
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1answer
43 views

Populate a networkx graph with tuples of varying lengths

I've got a list with tuples of variable length containing nodes, out of which I want to build a network: ...
10
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1answer
90 views

Detecting cycles in a directed graph without using mutable sets of nodes

I recently came across the classic algorithm for detecting cycles in a directed graph using recursive DFS. This implementation makes use of a stack to track nodes currently being visited and an extra ...
5
votes
1answer
71 views

Sort a scrambled itinerary (Google apac test problem)

This is my first time writing ruby - and I was mainly hoping to get some feedback and stylistic pointers. The algorithm is pretty straight-forward, since Google guarantees airports aren't repeated I ...
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2answers
54 views

Shortest path algorithm in 0-1-unoriented graph

I have an unoriented graph with n vertices and m edges, 1 <= n, m <= 100000. All edges ...
3
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1answer
86 views

Graph data structure implementation

I just started using C++, and I was wondering if my code fits the standards so far. Specifically, I was wondering if I did the addEdge, ...
8
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1answer
147 views

A rapidly-growing script that visualizes WiFi sniffing

Below is one of the versions of my wifimap script: ...
1
vote
1answer
53 views

Graphs processing in Scala

I've just started to learn Scala and decided to implement small graph library to train. Here is the basic version, that describes graph and nodes structure and also provides implementation of ...
1
vote
2answers
61 views

Data loading Hash Map

I'm trying to improve my code's performance, and I've found an area where the execution time is being significantly increased. I've had a look through the code but I can't see how I can improve it. ...
0
votes
1answer
52 views

Plotting a trigonometric function appears to be too slow

This calculates the mobility and it's derivative of one element. If I calculate with 1 value of w, it's very fast. ...
2
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1answer
180 views

Graph representation using adjacency list for BFS, DFS, and Karger's algorithm

I want to implement some graph algorithms for learning purposes (e.g BFS, DFS, Karger's min-cut algo) and before diving into them I want to make sure I have got the graph representation right (using ...
2
votes
2answers
107 views

Implementing Directed and Undirected Graph in C++

I am learning C++ and I decided to implement a Directed and UnDirected graph. (I haven't learned how to do inheritance yet, so they are distinct classes.) I have not handled any error cases (i.e. ...
3
votes
2answers
61 views

A* versus Bidirectional Dijkstra's algorithm

I have added bidirectional Dijkstra's algorithm into my pathfinding "framework", and I would like to make good use of C++ programming idioms, eliminate all possible memory leaks, otherwise improve ...
2
votes
1answer
62 views

Generic pathfinding framework in C++

I have this generic framework for finding (weighted) shortest paths. Also, the program demonstrates the performance of A* and Dijkstra's algorithms on a directed weighted graph. Both run in ...
3
votes
1answer
66 views

Yet another graph search

I noticed there were already countless implementations of graphsearch procedures on here, but there were a couple of features of my approach that I haven't seen in the others, plus I would greatly ...
1
vote
3answers
190 views

Adjacency matrix on undirected graph

Please review my Adjacency Matrix class based on this code. Since I use std::vector to create the matrix, I would like to store as many nodes as possible. Is it ...
1
vote
1answer
82 views

Creating an adjacency list in C++

I want to create an adjacency list based on data I get from a text file. Could I make this simpler? ...
3
votes
1answer
101 views

PHP implementation of “depth-first search” on the graph data structure

As I am a totally self-taught 'person writing code', I decided to learn algorithms with one online course that taught them using Java for demonstrative purposes. The first topic I covered is the graph ...
5
votes
1answer
102 views

Strongly connected components, component graph, semiconnected graph and new graph from SCCs

I have written a program in C to do the following: Read a matrix (in file format, first line you have the size, then next are the entries). This is done by the "input" function. Find the strongly ...
2
votes
2answers
122 views

Graph adjacency list implementation in C++

I have been playing around with an adjacency list implementation of a graph class, on which I'd like to be able to run a build and test several graph algorithms. The code I have below works and I have ...
3
votes
1answer
2k views

Shortest path using Breadth First Search

I have sample graphs like the following(Un-directed un-weighted cyclic graphs). My goal is to find shortest path between a given source and destination. ...
3
votes
1answer
82 views

Graph Adjacency List

Spent some time implementing a graph as an adjacency list. Looking for suggestions on how to improve this implementation. ...
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2answers
68 views

Passing text through a network of transformation modules (task #4)

About a year ago, I was given a C++ assignment as a preliminary job-interview test. The assignment included 4 different tasks, from which I had to choose one. I actually chose and completed 3 out of ...
2
votes
2answers
125 views

DFS Undirected Graph

The code included below was written in response to a programming exercise that was sent to me by a company that I am applying to. The purpose of the code is explained at this link. This code passes ...
3
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1answer
2k views

Depth First Search and Breadth First Search in C++

I am trying to learn DFS and BFS. However, I just want to make sure that I am not doing anything wrong. Would you please determine if the BFS and DFS functions are correct? ...
1
vote
1answer
122 views

Networkx VS graph-tool

I'm working on graph mining, so I'm trying to find the best library to do that. I've read in here that "graph-tool" is faster, so I tried the same program who count the duplicated graphs (I call them ...
2
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0answers
117 views

Efficient compile-time directed graph

During my research in Rigid Body Dynamics, (where Contact Graphs are used to solve the contact problem) I came across the question if it is possible to define at compile time a directed graph (class) ...
3
votes
1answer
66 views

Removing graph nodes of a specific type and with exactly two neighbors

I am working with an undirected, weighted graph. It contains two types of nodes, called "A-type" and "B-type". I am starting with a set of tuples of the following ...
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0answers
50 views

Minimum amount of edges that needs to be traversed to visit all vertices… or something like that

So I have this problem, where I'm given m connections over n vertices. The vertices are labeled ...
4
votes
1answer
229 views

Shortest path through a maze

I was trying to solve this problem in Java: Given a 2-D array of black and white entries representing a maze with designated entrance and exit points, find the shortest path from entrance to exit, ...
1
vote
1answer
166 views

Creating a graph in Java

I'm building an application that implements the A* algorithm to calculate a route between two rooms. I am trying to create a graph which the algorithm can operate on and I am not sure if this is the ...
4
votes
1answer
457 views

Directed acyclic graph with topological sort

I have here a class which represents a directed acyclic graph (Graph) and a vertex in the graph (Vertex). The vertices are ...
3
votes
2answers
176 views

Determining if there is a route between two nodes in a directed graph

This algorithm should return a boolean value, telling if there is a path between two nodes in a given directed graph. ...
2
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1answer
68 views

Improving time complexity of cheapest travel route algorithm

Below is the code to find the cheapest route for a passenger. stationsUnexplored is a Queue to which stations are added and ...
3
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0answers
149 views

Bidirectional Edmonds-Karp algorithm in Java

The Edmonds-Karp algorithm relies on breadth-first search in order to find an augmenting path in the residual flow network. This version of the algorithm uses bidirectional breadth-first search in ...
2
votes
0answers
95 views

Kruskal's algorithm in Java - follow-up

The previous and initial iteration at Kruskal's algorithm in Java Now what I did is remove the fields and let the actual Kruskal-routine create the required data structures in the local scope, ...
3
votes
1answer
891 views

Dijkstra's algorithm in Python

I was hoping that some more experienced programmers could help me make my implementation of Dijkstra's algorithm more efficient. So far, I think that the most susceptible part is how I am looping ...
3
votes
3answers
328 views

Pouring water between two jugs to get a certain amount in one of the jugs

I wrote a solution for a jug problem (given two jugs of water of different sizes find the steps needed to get specific amount of water in one of the jugs). I'm hoping for some input on my code. How ...
2
votes
4answers
4k views

Depth-first search in Python

I wrote this DFS in Python and I was wondering if it correct. Somehow it seems too simple to me. Each node is a class with attributes: visited: Boolean ...
1
vote
0answers
69 views

Max independent set of a sequence

This is the code I've written to find the maximum-weight independent set of a graph path. It's a standard problem with a well-known dynamic programming solution of linear complexity. Since it's a ...
4
votes
0answers
90 views

Finding cycles in a graph that pass through a vertex at most k times

I have a project that relies on finding all cycles in a graph that pass through a vertex at most k times. Naturally, I'm sticking with the case of k=1 for the sake of development right now. I've come ...
2
votes
1answer
80 views

Calculating Euclidean distance and performing unit-testing

The method creates a link, an edge between two nodes, and calculates the Euclidean distance. I'm testing that after linking, the link does indeed exist, and that the distance is correct. I've used ...
1
vote
1answer
113 views

What could I possibly change with this BFS and code to enhance its performance?

This code is supposed to find, in a graph, the node with the smallest maximum distance to all the other nodes. The problem can be found here. For instance, in this example graph: 2 is the node ...
0
votes
1answer
109 views

Iteratively-Deepening Depth First Search (queue and non-queue)

I am aware that most 'generic' BFS algorithms that use a queue also check for uniqueness of visitation to 'speed things up' as it were, but I'm a bit unclear as to how to implement such a method as ...
10
votes
1answer
408 views

Graph implementation adjacency list 2.0

Version 1: Graph implementation adjacency list 1.0 Please note the following: All edges are directed A user of the class Graph shall never be able to aces an object of type ...