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.

learn more… | top users | synonyms

3
votes
1answer
33 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? ...
0
votes
1answer
27 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
votes
0answers
50 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) ...
1
vote
0answers
12 views

Removing Graph Nodes of a Specific Type and with Exactly Two Neighbors

Problem Description 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 ...
1
vote
0answers
46 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
59 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
51 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 ...
3
votes
0answers
64 views

Shortest path for every source-destination (s-d) pair in a network?

I am working on Dijkstra algorithm and trying to find the shortest path for every source-destination (s-d) pair in a network. I have the below code which is working fine. ...
2
votes
0answers
20 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
43 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
votes
1answer
43 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 ...
2
votes
0answers
36 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 ...
3
votes
0answers
41 views

Edmonds-Karp algorithm for maximum flow in Java [duplicate]

I have this implementation of Edmonds-Karp algorithm for finding maximum flow in networks. It runs in \$\mathcal{O}(VE^2)\$ time. What do you think? AbstractMaximumFlowFinder.java: ...
2
votes
0answers
36 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, ...
2
votes
1answer
100 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
123 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 ...
1
vote
4answers
510 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
28 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
51 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 ...
1
vote
1answer
62 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
94 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
40 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 ...
5
votes
0answers
91 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 ...
2
votes
1answer
31 views

Parsing DAG from text

This module allows to parse indented text file into Map from node to child nodes identified by Coordinate. This module seems way ...
2
votes
1answer
46 views

Small generic path search framework in Java

I have this small generic path search library. It's not perfect at all, so I need some comments as to have a chance to improve it. com.stackexchange.codereview.graph.model: ...
3
votes
2answers
112 views

Implementation of Dijkstra's algorithm to find the shortest path in graph

This is my implementation of Dijkstra's algorithm in C++. Please clarify Whether the class design is proper or if it needs to be improved. I am just hard coding the vertex based on the priority of ...
2
votes
1answer
82 views

Optimizing for data import in Neo4j using py2neo

Here is my code for importing from a .csv to a neo4j graph using py2neo and cypher statements. I've noticed that it slows down significantly the bigger the graph gets. It takes several seconds just to ...
4
votes
0answers
102 views

Dijkstra's algorithm in PHP

This is Dijkstra's algorithm in PHP. Regarding the data structure, I use a 2-dimensional array $_distArr[m][n]=length to store it. Are there any improvements for ...
2
votes
1answer
77 views

Very slow graph walking

My code is very very slow. Could you give me hints on how I can make it much faster? ...
7
votes
2answers
181 views

Kruskal's algorithm in Java

I have this Java implementation of Kruskal's algorithm. It solves a tiny problem instance correctly, yet I am not quite sure, whether my implementation is correct. The code as follows: ...
2
votes
1answer
155 views

Graph implementation adjacency list 1.0

Please note the following: All edges are directed Removal of edges/nodges is not implemented yet A user of the class Graph can never (hopefully) access a ...
-1
votes
2answers
87 views

Cycles of pointers

I'm really inexperienced with cycles, so I want to make this code shorter. As far as I know, I've made a recursive cycle. ...
1
vote
0answers
30 views

A scalable function for get boundary vertices in a graph

Given a community division I need a list of vertices that have edges in more than one community, i.e., boundary vertices. I've tried this: ...
7
votes
3answers
88 views

Removing equivalent authors in a list

I have a list of authors, where seeking duplicity. The indexes of these duplicates are stored in a list of lists named duplicity. For example, at index 0 in the list duplicity is nested list, which ...
1
vote
1answer
108 views

Minimum Spanning Tree using Prim's algorithm and an indexed minimum priority queue

I have written some basic implementation of a Minimum Spanning Tree using a indexed minimum priority queue. For the implementation of the Priority Queue I used Sedgewick's Tutorials. However, it seems ...
3
votes
1answer
1k views

Shortest path Dijkstra's algorithm

I'm trying to implement Dijkstra's algorithm to find the shortest path from a starting node to the last node of a 250px by 200px raw image file (e.g. starting node = [0][0], ending node = [250][200]). ...
3
votes
1answer
221 views

Prim algorithm implementation for adjacency list represented graph

Please review the implementation of Prim algorithm. Points on which I have doubt: My Graph doesn't have any ID for nodes. Nodes are accessed based on their data. ...
1
vote
0answers
178 views

Kruskal algorithm implementation for adjacency list represented graph

Please review the implementation of Kruskal algorithm. Points on which I have doubt: My Graph doesn't have any ID for nodes. Nodes are accessed based on their ...
3
votes
0answers
76 views

Djkistra shortest path implementation for adjacency list represented graph

Please review the implementation of Djkistra algorithms. Points on which I have doubt: My Graph doesn't have any ID for nodes. Nodes are accessed based on their ...
2
votes
1answer
53 views

Extracting a subgraph

Given a huge graph, I want to traverse it, in the fastest way possible, and extract a subgraph with the following properties: the starting node is specified the maximum number of elements and max ...
1
vote
1answer
63 views

MinCostMaxFlow implementation is not fast enough

I'm trying to solve this problem: A root tree is a directed acyclic graph that contains one node (root), from which there is exactly one path to any other node. A root tree is binary if ...
5
votes
2answers
229 views

Constructing a graph and performing a depth-first traversal

Please review the use of pointers and design in graph construction code and its depth first traversal. I haven't used smart pointers as I want to understand any issues in following implementation with ...
0
votes
3answers
366 views

Dijkstra in C++ to find shortest path for every vertex of a directed graph

I am trying to implement the Dijkstra algorithm in C++ that finds the shortest path for a graph from a text file. The text file contains a matrix that represents a directed graph. What I am trying ...
10
votes
2answers
176 views

Is this Bridges code F# idiomatic?

Introduction I'm primarily a C# programmer, just starting out with learning F#. I found myself with a problem which felt like it was appropriate for a functional language, and now that I have the ...
4
votes
1answer
160 views

Adjacency-list graph implementation in C++ (redone from scratch)

I had posted here before, but I decided that the approach used earlier - where every Vertex stores a vector of pointers to ...
0
votes
2answers
374 views

Optimizing Dijkstra implementation using PriorityQueue in Java

I am trying to make Dijkstra implementation more efficient. Below is the code for class Node which implements Comparable so it ...
3
votes
1answer
85 views

Improving efficiency of Prim's Algorithm

I have implemented Prim's Algorithm in Java. I am wondering how it can be made more efficient. Below is the class Node for vertices. ...
4
votes
2answers
337 views

Minimum Spanning Tree using Prim's algorithm

I have implemented a Minimum Spanning Tree using Prim's Algorithm. Could someone give some about some improvements for code structure, conventions, performance, etc? ...
2
votes
2answers
98 views

has_cycle in directed and undirected graphs

I wrote a program that can tell if a graph has_cycle or not. Can you please suggest more elegant and eloquent ways for this program? (Perhaps better ways to represent a graph with vertices and ...
5
votes
3answers
491 views

Trip Advisor - Train routes

Gives advice to the user on which trains to take to reach a destination ...