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.

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3
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0answers
19 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, ...
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1answer
42 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
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1answer
73 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 ...
3
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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 ...
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1answer
45 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. ...
4
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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 ...
3
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1answer
80 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
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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. ...
3
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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
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1answer
34 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
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1answer
30 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 <...
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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
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1answer
71 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 ...
2
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2answers
155 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 ...
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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
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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
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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
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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 ...
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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
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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 ...
6
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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
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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
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1answer
137 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
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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
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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 ...
5
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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. ...
9
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5answers
254 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' }, ]; ...
4
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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: ...
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1answer
148 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 ...
3
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0answers
36 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
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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. ...
2
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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 ...
4
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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 ...
3
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2answers
177 views

Graph using adjacency list in Java [closed]

This is the main code. Here I'm joining vertices by edges. ...
4
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1answer
67 views

Swift Prim's algorithm

Lots of Prim's algorithm implementations seem long, and rely on a priority queue implementation. If I use an adjacency matrix I can then calculate the next item to take using functional programming ...
5
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0answers
60 views

graphtimer v2 - Utility to plot timings

GitHub repo (MIT) Clone the repo and replace the contents of example.py with the one at the bottom and you'll have everything setup. Explanation of the code A ...
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2answers
86 views

Determine whether a node is reachable

I am working on this HackerRank problem but running into time constraint issues. Basically, given two arrays, we need to determine if the ith element of the second array is reachable by the ith ...
5
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1answer
228 views

Graph puzzle resolver

I've solved test task for job vacancy. Need your feedback about my solution. Task The image below shows the puzzle in the solved state. The puzzle consists of 10 cells. Among the cells one is empty, ...
2
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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. ...
15
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3answers
342 views

Traversing an infinite graph using Dijkstra's algorithm to maximize cookie production speed

Imagine the following situation: It is the year 20XX. You are a prodigious baker, capable of baking cookies at an astonishing rate of 1 cookie per second. Your archnemesis, an equally excellent baker,...
5
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1answer
213 views

Dijkstra algorithm implementation in Swift

I've implemented Dijkstra's algorithm to find the minimum path between two nodes. ...
6
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1answer
80 views

Yet Another Dijkstra with real data and drawing

I've been assigned to use Dijkstra's algorithm in order to find the shortest path on real data, more specifically on Luxembourg's map. The map is an .xml file with the following structure. ...
0
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1answer
447 views

Get all node descendants in a tree

I have a CSV holding a "flat" table of a tree's edges (NOT binary, but a node cannot have two parents), ~1M edges: ...
3
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1answer
97 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 ...
2
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2answers
213 views

Dijkstra - shortest Path implementation - STL

I have implemented Dijkstra algorithm to perform Shortest Path problem. Input: Adjacency List(Directed Graph): Description is like that {Source Node, {edge_1, .. , edge_N}} Cost Matrix (Same ...
2
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1answer
333 views

Vertex Cover Problem Greedy Solution [closed]

As far as I understood this problem, it is a subset of vertices of Graph G, such that every edge has at least one endpoint in the subset. This problem is considered to be NP Complete. However I think ...
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1answer
47 views

Vertical Bar Graph Generator

I have created a python program that prints a vertical bar graph made from fields and values inputted by the user. It works by first creating a horizontal bar graph and then going through each layer ...
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0answers
58 views

Graph implementation from adjacency list

I've implemented a graph for a course and i'd like to know what i could improve. The graph is created from a adjacency list from a file with the following format per row: ...
1
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1answer
69 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 ...
3
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1answer
136 views

Map coloring with MRV and Degree heuristics in Python

I am relatively new to Python. I wrote this solution to the well known map coloring problem and also implemented the MRV and Degree heuristics. Here, I am considering the map of Australia - ...