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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12 views

Could anyone find a bug in my code for finding whether the graph is BIPARTITE or not ? [on hold]

I am solving this problem on spoj. The problem essentially tells to find whether graph is bipartite or not. I have written the code and tried many(really many) test cases but it seems to work ...
2
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1answer
40 views

Dijkstra's algorithm

Assuming everything else works as expected, is the following a correct - but not the most efficient way - of implementing Dijkstra algorithm? Because I have tested it on several examples and it gives ...
1
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0answers
18 views

Maximum clique problem: fast heuristic

I have implemented an algorithm which computes a maximum clique via a heuristic. The pseudo-code can be found in this Paper (see Algorithm 2). Maximum Clique Problem Given an undirected, simple ...
3
votes
0answers
17 views

Cyclic “dependency detection” in JavaScript

I have written some simple code to detect cyclic dependencies for a module loading system and I'd like some feedback on how I can go about improving it. The code itself finds the first cycle in the ...
3
votes
2answers
105 views

C++ Graph Class Implementation (adjacency list)

I've got a barebones C++ graph class implemented as an adjacency list. The graph consists of a vector of vertices. Each vertex has a vector of outgoing edges that store the destination vertex id. ...
4
votes
1answer
89 views

Algorithms to find various kinds of paths in graphs

I think many here are familiar with the graph data structure. Not very long ago, I implemented as an exercise a supposedly simple Graph application that does some traversals. To note, the most complex ...
3
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0answers
33 views

Time Limit Exceeded with shortest path algorithm

The problem: SHPATH You are given a list of cities. Each direct connection between two cities has its transportation cost (an integer bigger than 0). The goal is to find the paths of ...
-2
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0answers
51 views

Can anybody help me with this (graph theory)?

I am preparing for job interviews and learning Analysis and design of algorithms. I have solved many problems using dynamic programming and greedy methods, but I am struck with this problem and unable ...
1
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0answers
23 views

Checking whether a directed graph contains a cycle

I create a myGraph class as shown below. Then I created an instance of the graph by giving the adjacency list as a NSDictionary and then call the isGraphCycleFree method. Will this answer look good ...
1
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1answer
51 views

Graph and minimum spanning tree in Python

Here is my Graph class that implements a graph and has nice a method to generate its spanning tree using Kruskal's algorithm. I want to: Make it pythonic Improve readability Improve the abstraction ...
2
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1answer
87 views

Find shortest paths in a matrix using Dijkstra's algorithm

The problem is as follows: I have a matrix with impassable fields those are marked by the input. There is also a castle which reaches up the right side of the matrix. I have to find how many paths can ...
2
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1answer
52 views

Maxflow for baseball elimination game

I have a problem similar to the baseball elimination. Given some teams, the number of wins they have and the number of games they have left between each other I have to find for which team it is still ...
3
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0answers
39 views

Comparing linear time strongly connected component algorithms in Java

So I have implemented three linear time (\$\mathcal{O}(V + E)\$) algorithms for finding strongly connected components of a (directed) graph. A strongly connected component is just a maximal subset of ...
0
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1answer
38 views

Optimizing and accounting for edge cases in Dijkstra's algorithm

I just recently wrote a program to simulate how multicast routing works. The program uses a weighted graph to represent the network and simply runs it through the algorithm. I would like to know if ...
3
votes
0answers
12 views

Data Explorer query that makes bar graphs

I wrote a query for SEDE that I think is pretty cool. It uses the currently available graphing capabilities (scatter plots) to create a bar graph. I have used it as the subject for a self-answer on ...
4
votes
0answers
61 views

Pseudo-parallel depth-first search

I'm writing a small program, that generates a file containing an adjancency matrix, it then reads from that file, constructs a graph and does something like a parallel dfs on it. How can I make the ...
7
votes
1answer
53 views

Social network graph of characters in a novel

I wrote a C program that builds a social network graph of characters in a novel. The program takes two text files as input: a list of the names of the characters in the novel, and the file of the ...
0
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0answers
31 views

Adjacency List Graph Implementation for search

I wrote this adjacency list graph implementation to learn about implement path finding and graph search. I'm looking to fix any coding style / best practice issues, and performance issues. Also, the ...
4
votes
0answers
78 views

Plotting charts for a large data set

I have created an automated macro which takes vehicle crash data from a .csv file and automatically creates a pivot table and plots and compares it to the previous year. The code is approximately 1400 ...
1
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1answer
100 views

Implementation of Dijkstra's algorithm in C++

This is my implementation of Dijkstra's algorithm. Could you tell me what am I doing wrong and what should be fixed? I was not sure how to keep track of the shortest outgoing edge from a node and I ...
1
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1answer
64 views

Implementation of Prim's algorithm in C++

Could anyone comment on what could be done better and if I made any mistakes? ...
5
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0answers
70 views

Topological sort using recursive DFS

I am currently learning Graph algorithms by solving questions on online judges. The below code is for implementing Topological sort, using recursive DFS. Also, it is my first time with C++ STL. ...
4
votes
3answers
98 views

Idiomatic ruby to calculate distance to points on a graph

Can this code be made more like idiomatic ruby using methods such as map or inject? @random_tour is a variable length array of points on a graph: ...
4
votes
0answers
46 views

Simple graph in Rust

I have written simple code to construct a graph, but I think there are too many different types for such a simple task. In this code I need to store Node structs ...
3
votes
1answer
72 views

Detect cycle in undirected graph

Below is my code to detect cycle in an undirected graph. Could anyone please review and let me know if I have taken care of all the cases? The basic idea is to use DFS (non-recursive using stack) and ...
2
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0answers
50 views

Finding all paths between nodes in a graph

I wanted to write a function paths that returns the possible routes between two nodes in a graph. For example: ...
3
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1answer
99 views

Dijkstra's algorithm: traditional and bidirectional in Python

I have translated Dijkstra's algorithms (uni- and bidirectional variants) from Java to Python, eventually coming up with this: Dijkstra.py ...
0
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1answer
60 views

Simple weighted directed graph in Python

I have this simplistic Python class for representing directed weighted graphs (digraphs for short): Digraph.py ...
0
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0answers
70 views

Hierarchical Data to Graph

I am using vis.js to visualize some hierarchical data. I have created a recursive routine to add nodes and edges for each group and value in the dataset. I feel like something already exists for this ...
3
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0answers
67 views

Graph Library in C

Could you guys please review the Graph Library I developed in C? It's also on GitHub ...
1
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0answers
29 views

Minimum number of moves to reach the end - follow-up

I need to calculate the minimum number of jumps to reach the end of an array with dice throws. Array values may be negative/positive: When positive - move forward When negative - go back The ...
4
votes
1answer
44 views

Minimum number of moves to reach the end

I need to calculate the minimum number of jumps to reach the end of an Array with dice throw. Array values may be negative/positive: When positive - move forward When negative - go back The ...
3
votes
0answers
62 views

Implementation of Dijkstra's Algorithm in JavaScript that returns both shortestDist/shortestPaths

I decided to try to understand the basic idea behind Dijkstra's algorithm better so I implemented it in JavaScript (the only language I am proficient in as of now) so I could really see what was ...
2
votes
1answer
28 views

Distributed (asynchronous) averaging

This code simulates a distributed averaging protocol. There is a network of nodes, and at the clicks of a Poisson process: A random node wakes up Transmits it's current average to all the nodes it ...
4
votes
1answer
129 views

Using the A* algorithm to search a graph generated from a grid

Following on from my previous question, I finally got round to actually doing the A* search for the Graph<MapTile>. The changes to the code from the previous ...
3
votes
1answer
72 views

DFS algorithm too slow

I am practicing my coding on leetcode, and my submission, although correct for small cases, is timing out for large ones. Could you please let me know how to improve my code? The question is as ...
3
votes
2answers
66 views

Generating a graph from a rectangular grid for graph searching

I recently reviewed some code implementing some heuristics which has piqued my interest in the A* graph searching algorithm. I'm going to do that in a bit but first I need a way to create a graph in ...
3
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1answer
75 views

A graph representation of Adjacent Matrix in Python

I'm trying to create a graph representation in Adj Matrix in Python. I'm not sure if this is the best pythonic way. ...
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0answers
39 views

Depth Limited Search for Map Coloring Graph in Python [closed]

Hey I'm trying to solve the Map Coloring Problem using a Depth Limited Search. I found an example of the problem here (https://courses.cs.washington.edu/courses/cse473/10au/slides/chapter05-6pp.pdf), ...
1
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2answers
63 views

Check if the undirected graph is cyclic

Here is my approach. Do DFS and check in stack whether the new node is already in the Stack or not. ...
1
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1answer
42 views

Check directed graph is tree or not

Here is my approach. 1. Checking there is no cycle.(Using BFS) 2. All nodes are connected. (visited) ...
3
votes
0answers
100 views

CLRS(Introduction To Algorithms) implementation of BFS and DFS in Java

This is the implementation of BFS and DFS i have tried to follow from CLRS.Please suggest what can be improved in this code. ...
0
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2answers
60 views

Check if path exists directed graph, without using collection

I have written code to find whether the path exists between source and destination in a directed graph. I have used BFS and instead of ArrayList or queue. I have ...
5
votes
1answer
78 views

Find the largest continuous descending sum in a 2d matrix

Given a 2d array, the problem is to find the largest sum, where each subsequent is >= the previous digit but < all of the 'neighbour' digits. You can only move up, down, left and right. My ...
2
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1answer
79 views

Finding smallest number of moves

We are given a map of sides of length n and m (both n and m are less than 1000), divided into n*m fields (squares of side 1). The map looks (for example) like this: ...
5
votes
3answers
391 views

“Researcher Hatim is right or wrong” challenge

I wrote a program to solve a problem, I am not so good in python so want help to find areas where this program can be improved or simplified and readable too:- I got this problem in a code challenge ...
2
votes
1answer
79 views

Find all the countries I can visit by just crossing direct borders

I was helping on this question. There you have a table border to indicate countryA and countryB have a common border. And want ...
1
vote
1answer
84 views

Computing the distance and weight matrix of a graph

I would like to create an igraph object. First, I set up the size of igraph object — n, m, then create a random matrix. As a result matrix ...
2
votes
0answers
83 views

Dijkstra algorithm implementation in F#

I'm trying to implement Dijkstra algorithm in F# for finding the shortest path in a undirected tree using a heap. I've used the type PriorityQueue found here and the code can be found here. ...
2
votes
0answers
103 views

Dynamic graph in C++11 with shortest path algorithm

I've been designing a dynamic graph to improve my understanding of C++11. The dynamic aspect means that it could represent the hyperlink structure of a chunk of the internet, with node deletion ...