Questions tagged [graph]

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.

Filter by
Sorted by
Tagged with
2
votes
0answers
31 views

Finding connected components of a graph

I have a graph represented using a dict of sets, e.g. ...
1
vote
1answer
78 views

Graph Implementation in Java using Set and Map

There is a Graph implementation. I'm using Set to store unique Edges and Map to store Vertices and their associated edges. Assume Vertex and Edge class has been defined somewhere else implementing ...
4
votes
1answer
44 views

Finding all simple (without internal cycles) paths in a directed graph with total >1.0 weight

Assume directed graph with each edge being weighted by some positive float. Problem: find all simple paths (in other words, ...
4
votes
0answers
88 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 ...
6
votes
0answers
536 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 depth-first search (dfs) on it. ...
1
vote
1answer
49 views

Graph implementation for solving graph problems (java)

I've currently started solving some competitive programming Graph questions. But Started using adjacency list as HashMap<Integer,ArrayList<Integer>> list...
4
votes
0answers
2k 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: ...
5
votes
1answer
420 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 ...
3
votes
0answers
38 views

Django project for events of the day, grouped by keywords in common

I have made a website where people write about their day and see it analyzed. In particular, the website takes event titles and groups them together if they have any common words (after stemming the ...
4
votes
1answer
80 views

Change tracking POCO entities

Description In a time where thin clients, web browsers, web services and micro services are prevalent, we tend to forget we still have to deal with thick and smart clients. Many applications in B2B ...
6
votes
1answer
123 views

Add an edge to a graph to minimize the average shortest path length

This program is used to find the nodes in a grid network, between which, if an edge is added, the average shortest path length of the entire grid reduces by the most. "Average shortest path length" ...
4
votes
1answer
62 views

Maximum profit earned on weighted un-directed tree

I came across this problem while giving a sample test. The problem was that we have given a tree which is undirected. We can start from any node of our choice. Initially we have power "P" and ...
1
vote
3answers
4k 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 ...
2
votes
1answer
81 views

Dijkstra implementation for large graphs

I am implementing the Dijkstra algorithm for a large graph (40k nodes, 100k arcs). For shorter paths the searchtime is under a second for larger ones (from one end to the other) it takes quite some ...
1
vote
1answer
47 views

Dijkstra's implementation in c++ with STL priority_queue

This is dijkstras shortest path algorithm implementation in c++ using priority_queue STL. Looking for two things: a) Correctness of algorithm itself and b) Any improvement suggestions. ...
3
votes
1answer
81 views

CodeChef's Tree MEX (Minimum Excludant) challenge

This code is a solution for CodeChef's Tree MEX problem: Minimum excludant (or MEX for short) of a collection of integers is the smallest non-negative integer not present in the set. You ...
3
votes
1answer
38 views

Wiki Link Mapper — A webcrawler which crawls links recursively and prints them into a graph

I would like some suggestions on how to make it better and also if any features that i should add to this Script. I am using beautifulsoup,requests for scraping and networkx for plotting the graph. ...
1
vote
0answers
31 views

Benchmarking k-shortest path algorithms in Java without JMH

In this post, I have the demo driver that benchmarks two \$k\$-shortest path algorithms. The entire GitHub project is here. net.coderodde.graph.kshortest.Demo <...
3
votes
1answer
41 views

Kruskals MST Algorithm

This code computes the Minimum Spanning Tree of a given graph using Kruskals Algorithm. It works successfully and I have provided test cases within the code. I would like feedback on code efficiency ...
2
votes
1answer
36 views

Find cycles in Graph using Union Find Algorithm on Adjacency List

My code detects if a cycle is present in a graph using Union find algorithm with Weighted tree analysis and path compression. It works and I have included test cases. ...
2
votes
1answer
31 views

Find articulation points/ cut vertices in graph

I would like to get some feedback on my completed code that finds and displays the articulation vertices in an undirected graph. I included a test case within the code, it should (and does) print <...
2
votes
1answer
58 views

Modelling Immerman–Szelepcsényi in Haskell

I am trying to model the proof of Immerman–Szelepcsényi Theorem with Haskell since it heavily uses non-determinism. An explanation of what the point of this is can be found here. ...
1
vote
0answers
49 views

Graph-coloring solution using depth-first search

I'm trying to solve this question: Andryusha goes through a park each day. The squares and paths between them look boring to Andryusha, so he decided to decorate them. The park consists of n ...
2
votes
1answer
74 views

Kruskal MST algorithm

I came up with the following code by following Prof. Sedgewick's lecture on Coursera. Please review this code and let me know if there is anything that I got wrong in implementing Kruskal's ...
5
votes
1answer
659 views

Strongly connected component finding based on the guava graph library with Kosaraju

I have been writing a small compiler generator for which I need to solve the strongly connected component problem. As the Guava library contains, to my knowledge, no implementation for that problem, I ...
2
votes
2answers
165 views

Geektrust: Modelling Family Relationships in a OO way

I'm trying to model family relationships in a OO way, i.e. As we update the relationships between two individuals our model must be able to find the people given a person and the type of relationship ...
3
votes
1answer
98 views

Implementation of generic Graph class and Dijkstras

I participate in competitive programming contests, and I found myself implementing and re-implementing graphs constantly. So I decided to create a reusable implementation of a Graph class, and ...
3
votes
0answers
48 views

Graph Search in C++17

Overview I am constructing a Graph with randomly generated nodes called Positions. The Graph has a width and a height and is represented using an adjacency list <...
5
votes
0answers
153 views

Assembling and traversing a graph, given a list of items and parent pointers

I've written a function which takes input such as this: ...
4
votes
2answers
115 views

Heights of Cats

I have an assignment to solve this problem. However, I have exceeded the time limit required, can anyone suggest where to improve my code? Cats like to sit in high places. It is not uncommon to see ...
5
votes
1answer
76 views

3-function program computing connected components of a point cloud given a distance matrix

I wrote this code in Haskell (instead of Python) for the educational benefit. Can anyone suggest ways to improve this code? I'm guessing that I'm using fromIntegral...
2
votes
0answers
24 views

Modelling a program with modules, symbols, and dependencies

My scenario is the following: I'm modelling a Program which has many Modules. Each Module has Symbols, some of which pointing at dependencies, which are other Modules. So a Module can be pointed to by ...
1
vote
2answers
88 views

Dijkstra's Algorithm C++

This is a basic implementation of Dijkstra's Shortest Path Algorithm for Graphs. I am looking for any kind of improvement. ...
2
votes
2answers
43 views

Graph library - graph interface

I am trying to write simple graph lib in C++, BFS, DFS etc.. I want to create class GraphI which will represent any graph and will include necessary methods so my ...
2
votes
1answer
51 views

Maximize Path Value

I recently had to code an algorithm that will, for an input of: matrix of up to 5x5 size and a defined path length, find a path of this given length from the first top left matrix element (0, 0) to ...
6
votes
1answer
118 views

Longest carbon chain

My Code measures the longest path, not allowing cycles. For the example input below, the longest chain would be 4 Please can you review my code? ...
3
votes
1answer
50 views

Find number of islands Leetcode

Here is the question: Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally ...
7
votes
1answer
142 views

Hackerrank: Computer Game (max-flow problem with integer factorization)

I am working on a coding challenge from the Hackerrank site. Given two equal-length arrays of integers, with values from 2 to 109, find the maximum number of times we can remove a pair (Ai, Bj) where ...
2
votes
1answer
99 views

Graph implementation using FIFO lists

I've made a little implementation of an undirected graph, using FIFO lists, for one of my homeworks. Never really knew how to write a proper FIFO data structure, so I would be glad to see some opinion ...
2
votes
1answer
34 views

Strongly connected component in graph

My goal is to calculate the length of each strongly connected component (SCC) I have an input that looks like this: ...
2
votes
1answer
316 views

Adjacency list graph in Java

I am reading a text, that from a higher level explained adjacency list implementation of a graph. I have now tried to implement this as simply as I could. I did not see any reason to have an actual ...
5
votes
1answer
64 views

Optimizing graph partitioning by connected components of generated subgraph

I'm trying to optimize a function in a process which is going to be run millions of times. The function is supposed to partition the vertices of a graph, which will be used to make a quotient graph. ...
1
vote
2answers
59 views

Find CISC prerequisites

Below I have some code written in prolog as a brief example. The goal of the program is to take a Computer and Information Science (CISC) course number and return any CISC prerequisites (prereqs). I ...
8
votes
3answers
1k views

Reorder a list of courses, given their prerequisites

I recently graduated from college and applied for a position with a company. I was sent a coding exercise as part of the process. After completing the exercise and submitting it I was told that the ...
9
votes
5answers
255 views

Sort a list of pairs representing an acyclic, partial automorphism

I have this sample data: let trips = [ { from: "DEN", to: "JFK" }, { from: "SEA", to: "DEN" }, { from: 'JFK', to: 'SEA' }, ]; ...
1
vote
1answer
153 views

Leetcode online Find the judge, graph with highest degree

Here is the problem. In a town, there are N people labelled from 1 to N. There is a rumor that one of these people is secretly the town judge. If the town judge exists, then: The town ...
4
votes
1answer
86 views

C++ graph class

What can be done better? My future plans is to implement algorithms such as: DFS, BFS, Prims, Dijkstra, Kruskal, ... Faults I know of: Not implementing rule of five Vertex.h: ...
3
votes
0answers
37 views

Two solutions to leetcode 127.wordLadder

I am working on Word Ladder - LeetCode Given two words (beginWord and endWord), and a dictionary's word list, find the length of shortest transformation sequence from beginWord to endWord, such ...
2
votes
1answer
43 views

Kahn's algorithms to arrange CouseSchedule

I wrote a solution to Course Schedule II - LeetCode There are a total of n courses you have to take, labeled from 0 to n-1. ...
5
votes
1answer
538 views

Dijkstra finding shortest path satisfying given constraints

The question is originated from Hackerrank. Suppose there are 1 to N stores in a city which are connected by bidirectional roads associated with traveling ...