Directed Graph Cycle Detection
Jan 4, 2015
I have some problem checking if a directed graph has a cycle or not. So I have a given rooted directed graph, and find if there at least one existing cycle.
For example, I have to input the Root Node, followed by a number of nodes, the nodes in the graph, number of edges, and the adjacency list representing the edges. Each entry in the adjacency list contains a pair of nodes. The ordering of the nodes in the pair represents the direction of the edge. An entry A, B means that there is an edge from A to B. Nodes in each pair is separated by a space. One input per line.
And the output should display whether the directed graph has a cycle or not.
Sample input:
A //Root Node
6 //Number of Nodes
A //Nodes in Graph
B
C
D
E
F
6 //Number of edges
A B //Adjacency list representing the edges
B C
C D
C F
F E
E B
Output:
Cycle!
Graph Representation:
Based on the illustration above, the graph has one cycle. The cycle exists in nodes B, C, F and E.
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Aug 6, 2014
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[Code] ....
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package com.questkings.game;
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[Code] .....
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[Code] ....
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[Code] .....
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[Code]...
--- Update ---
Actually i'm using netbeans...
--- Update ---
and the datas are coming from a text file...
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graphs.txt
6,1
0,2 0,4 1,4 1,5 2,1 2,3 2,5 3,2 3,4 4,1 4,5 5,1 5,3 5,2
import java.io.File;
import java.util.Scanner;
public class Vertices {
public static void main(String[] args) throws Exception {
@SuppressWarnings("resource")
[Code] ....
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[Code] .....
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"graphs.txt"
6,1
0,2 0,4 1,4 1,5 2,1 2,3 2,5 3,2 3,4 4,1 4,5 5,1 5,3 5,2
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class AdjList {
private Node first; // beginning of list
[Code
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[code]....
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May 2, 2014
I'm trying to print the number of vertices in a text file on a graph which is the first integer in the file and then the type of graph is an undirected graph for a 0 or a 1 for a directed graph. Right now I'm just trying to print the number of vertices which is a 6 in the text file.
Here's the text file:
6,1
0,2 0,4 1,4 1,5 2,1 2,3 2,5 3,2 3,4 4,1 4,5 5,1 5,3 5,2
Im getting the following error:
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 6, Size: 0
at java.util.ArrayList.rangeCheckForAdd(Unknown Source)
at java.util.ArrayList.add(Unknown Source)
at Vertices.main(Vertices.java:21)
Then I need to know how to go about reading the next line in the file, do you read it with the nextLine and put it into an arrayList or do I read each index in the graph?
public class Vertices
{
public static void main(String[] args) throws Exception
{
Scanner inFile = new Scanner(new File("graphs.txt"));
// Read the number of vertices
String line = inFile.nextLine();
ArrayList<Integer> list=new ArrayList<Integer>();
String[] data=line.split("[\,]");
int numberofvertices=Integer.parseInt(data[0]);
int typeOfGraph=Integer.parseInt(data[1]);
list.add(numberofvertices,typeOfGraph);
System.out.println("The number of vertices is " + numberofvertices);
}
}
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Attached File(s)
data.cvs.txt (726bytes)
Number of downloads: 12
chart.txt (3.72K)
Number of downloads: 10
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