a mathematical structure that contains a collection of vertices or 'nodes' and a collection of edges that connect pairs of vertices

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46 views

The maximum number of induced cycle in a simple directed graph

Given a simple directed graph G=(V,E) an induced cycle is a cycle where no two vertices of the cycle have an edge that is not in the cycle. (Chordless cycles are induced cycles with at lease 4 ...
4
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1answer
200 views

Are there multiple Hamiltonian Paths on a Graph?

Can anyone suggest an algorithm for this problem. Given an undirected unweighted cyclic graph, and a given start and end node in that graph, I'd like to determine if there is exactly one valid path ...
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1answer
71 views

Yen's k shortest paths algorithm

I'm currently trying to understand Yen's k shortest paths algorithm. I based myself on the original paper as well as on the Wikipedia article, but still cannot see why it is correct if k > 2. In fact, ...
4
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1answer
135 views

Word ladder efficency problem

I have a problem dealing with word ladders. The problem is: given two words and a dictionary file, find the shortest word ladder between the two words. So if given the words cat and pot: cat -> ...
4
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0answers
70 views

Modelling a complex schedule of work

I've got a real-world problem that I'm trying to represent and automate. I've simplified and abstracted it down to the following: There are n places of work (P1, P2, ..., Pn). Each place, Pn has a ...
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3answers
211 views

Algorithm to determine the fastest route passing in all points

Given a starting point A and an end point E, I need an algorithm to determine the minimum transit route in a city that passes through all points (A, B, C, D, E) and is the fastest possible. I know I ...
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1answer
47 views

Dynamic Programming: Shortest path with exactly k edges in a directed and weighted graph

I came across this problem of finding the shortest path with exactly k edges. After some searching, I found the code below. It uses a 3D DP. States are there for number of edges used, source vertex ...
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1answer
37 views

Partition edges into areas

If I have a series of edges that branch and curve, such as in a road network, is there an algorithm that will identify the areas (defined by sequence of geographic points) defined between those lines? ...
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1answer
61 views

How many vertices/nodes are too many in a graph and stop being beneficial?

Background I'm working on a project that requires me to keep track of transactions as well as the flow of items in a game. In order to do that, I'm storing those transaction in a graph db ...
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39 views

Benefit and graphical representation of directed acyclic graph in code development

I think the relationship amongst the modules of a code can be represented by a directed acyclic graph (DAG) where a vertex represents a module and a directed edge from vertex a to vertex b represents ...
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2answers
108 views

The way to implement a configurable (at run-time) default style

I am coding a visualizer of graph algorithms. Each vertex of the graph has a style (color, size etc.). As long as the algorithm has done nothing to a vertex, that vertex has a default style. The ...
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0answers
73 views

Determine equality of a DAG

Given a fairly traditional node class (below), whats the best way to implement equality on a given graph? If our node looks like this public abstract class Node{ private final Set<Node> ...
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81 views

Decision making algorithm

I'm currently solving an optimisation problem of my own design, just to experiment and learn a little something. Here's the concept: I have a user that starts at home. The objective of this user is ...
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135 views

Algorithm to generate Edges and Vertexes outwards from origin with max multiplicity of 3

I am creating a 2d game for a website where the universe can grow extremely large (basically infinitely large). Initially, the universe is composed of 6 stars that are an equal distance from the ...
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0answers
43 views

Graph grouping with criteria

I start with a list of adjacent tetrahedra, where there are tight seals to one another along faces for two tetrahedra that are adjacent. The vertices belonging to these faces for both tetrahedra are ...
4
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1answer
131 views

Single Source Shortest Path

In the lecture we are taught that we can solve All Pairs Shortest Path(APSP) with matrix multiplication. In APSP we are creating a distance table for all the distances between each nodes in the ...
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2answers
337 views

Workaround for implementing operations on doubly linked or circular data structures in languages with immutable data

I would like to learn how to make graphs and perform some local operations on them in Haskell, but the question is not specific to Haskell, and instead of graphs we may consider doubly linked lists. ...
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2answers
245 views

How to optimize/parallelize the following clustering/joining algorithm:

I have relatively-small algorithm that takes up ~60% of the total run-time of my scientific code (57 lines of 3600), so I would like to find a way to optimize what I'm doing and make the code ...
3
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1answer
94 views

Are these graph coloring algorithms equivalent?

Suppose you want to color the vertices of a graph in a greedy fashion, given a predetermined order of these vertices. The goal is to avoid giving two adjacent (linked by an edge) vertices the same ...
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1answer
153 views

undirected c++ graph with a direction [closed]

I want to create a Graph in C++ that has directions, with directions I don't mean the direction of an edge but what I want is an undirected graph where the edges have a direction to the next vertex, ...
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0answers
88 views

Belman-Ford 2d array variation problem

I've got a problem with applying a Bellman-Ford algorithm to 2D Array (not to graph) Input array has m x n dimensions: s[1,1] s[1,2] ... s[1,n] -> Exit s[2,1] s[2,2] ... ...
2
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0answers
40 views

Filter out noise in line graphs

I have a question regarding finding relevant events in a line graph. The following graphs show the views (y-axis) of a video over time (x-axis). Certain events lead to an huge increase in views and ...
2
votes
1answer
273 views

Dependency ordering algorithm of a compiler

Let's say, hypothetically, I'm writing a Java compiler. And we assume that in my case a class can't be fully compiled until all signatures of dependencies (imports and other used classes) are known. ...
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1answer
59 views

How an add vertex operation could be performed in constant time for a graph represented using adjacency list?

Adding a vertex in a graph that is represented using an adjacency list takes O(1) time complexity according to http://bigocheatsheet.com/ (graph operation > adjacency list > add vertex). It is said ...
3
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1answer
205 views

why adding a vertex in a graph represented using an adjacency matrix takes O(|v|^2) time complexity?

Adding a vertex in a graph that is represented using an adjacency matrix takes O(|v|^2) time complexity according to http://bigocheatsheet.com/ (graph operation > adjacency matrix > add vertex). But ...
2
votes
1answer
237 views

Does a tree node have an ancestor?

Below is a rooted tree, where any node C except root has one parent P Ancestors of a node C are the nodes on path from C to root, including P,P's parent,P's grandparent, .... till root. My ...
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134 views

Approaches to Modeling a Graph Database over the Google App Engine Datastore?

I want to model a graph database over the Google App Engine Datastore. I am currently working on creating a Link entity to model the concepts of link/edge/relationship to the graph of objects. I am ...
2
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1answer
145 views

Efficient algorithm for hierarchical traversing? JSON hydration, for example

I'm writing a small library that helps you hydrate JSON data into objects. Given this JSON example: { "date": "1970-01-01 00:00:00", "foobar": "baz", "user": { "name": "foobar", ...
3
votes
1answer
230 views

Finding the optimal root

I am trying to solve a quora hackathon challenge question. The question descrpition is as follows : For the purposes of this problem, suppose Quora has N questions, and question i (1≤i≤N) takes ...
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1answer
34 views

How can I avoid needing to check for the existence another vertex when adding to an adjacency list?

I'm writing a Graph, and decided to make the Adjacency List its own class. Right now, (stripped down) it looks like this: public class AdjacencyList<Vertex> { //A map between a vertex, ...
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4answers
120 views

How definite of an order is there to a depth-first search of a graph?

I have the following graph that I need to simulate a depth-first search of; starting at g: My question is: How definite of an order is there when performing a depth-first search? When doing a DFS of ...
4
votes
2answers
292 views

Algorithm to find the optimal trade route (negative cycle with lowest cost per edge in a digraph)

Given the following problem (a slightly simplified description of trading in the computer game Escape Velocity: Nova (system map)): Given a set of (solar) systems. Each system is connected by ...
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1answer
129 views

Graphs and minimum spanning trees?

I am having a hard time finding information on how Graphs and spanning tree's work and how to construct/structure them. The reason is that I'm using a Delaunay Triangulation algorithm within the ...
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51 views

Graph curve and actual curve plotted on screen implementation patterns

I'm implementing a graph plotter. There are Curve objects, that contains points of actual XY data. When I plot to screen, I need to calculate the XY points on screen, resulting a PlottedCurve. This ...
4
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1answer
286 views

How to implement efficient heterogeneous microservice data queries?

Our team has an idea of implementing a simple declarative DSL that would let users query the enterprise's domain model via a single interface without caring which specific microservices to call to get ...
4
votes
1answer
188 views

Algorithm to find whether there is a path (any path) above length X between two vertices

We all know how to find the shortest path between two vertices, but what if I just want to know the answer to this question - is there a path, (any path), between vertex A and B of length larger than ...
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0answers
64 views

algorithm for group reassignment of points

I have a list of clustered points but they are not in the cluster which has the center closest to them. The objective is to reassign them to minimize the total distance of each point to its cluster ...
5
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1answer
228 views

Graph visualization algorithm

I need a 2d or 3d graph visualization algorithm by which adding/removing a node or a relationship does not have a butterfly effect on the positions of other nodes. (We are talking about a directed ...
5
votes
1answer
186 views

What is the maximum number of steps to find a bug using bisecting?

Assume that a node A in the commit tree of a codebase contains a bug but some ancestor B of A is clean from that very bug. Given the topology of the commit tree [B,A] leading from B to A, can we ...
0
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1answer
52 views

Render order of two-edge directed node graphs

I'm trying to find an algorithm for graphs with the following contents: Nodes with no edges leading out of them (shown here as a red circle) All other nodes have exactly two edges leading out ...
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0answers
77 views

All clustering possibilities for a graph

Is there a known algorithm for finding all clustering possibilities for a directed graph? EDIT: By cluster i mean a weakly connected sub-graph G, so that E(G) > 0. By a clustering possibility I ...
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0answers
49 views

Domination algorithm in graphs

I'm working on a project, on an app, that can visualize undirected graphs and show on this domination algorithm. There are some examples: I have some open questions about programmable solution of ...
1
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2answers
287 views

Big graph traversal with OOP

I'm trying to solve a algorithmic contest's problem. I have a matrix 2000x2000. I want to represent it as graph and traverse it with BFS/DFS. I have time limits on app running (2s). Simple vertices ...
7
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3answers
440 views

Algorithm or domain for finding cheapest subgraphs that connect vertex pairs

I am currently working on a project inspired by the Ticket to Ride board game. This board game is played on an undirected graph where each vertex represents a city and each edge represents a ...
1
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1answer
215 views

Connected components of undirected graph

Suppose I have an undirected graph G with vertices v1...vn and edges. Right now it is in adjacency list representation. For every time moment I have as input some subset of vertices that are "active" ...
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0answers
60 views

Codeforces : 505C. Mr. Kitayuta, the Treasure Hunter

Question : Is the attached logic correct? I am asking since my code based on this logic failed. Here is the problem link. Reproducing here verbatim : The Shuseki Islands are an archipelago of ...
3
votes
1answer
499 views

Is there some structured format for drawing source control branching diagrams?

Everyone on my team draws branch diagrams differently, including how branches exit or reintegrate to the parent, how cherry-pick merges are shown, and a host of other aesthetic choices. Is there some ...
1
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1answer
285 views

Why does this algorithm work in O(n m)?

This is from a blog post on Codeforces. I couldn't really understand why the editorialist goes on to claim that this code works in O(n m) This is a graph problem, where we are supposed to find the ...
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2answers
308 views

Why does this implementation of Dijkstra's algorithm work in O(n^2)?

Here is the code I use for implementing Dijkstra's algorithm. Consider a graph with n vertices and m edges. Shouldn't it run in O(n^2 m) ? Someone may say that there are n vertices and each edge gets ...
4
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1answer
134 views

Mathematically correct A* heuristic / distance estimator for a latitude / longitude graph

I have a graph in which each node is a geographical point on the surface of the earth, defined by it's latitude / longitude coordinates. Correct ways to calculate the distance between two such points ...