Java Programming Write a program to perform a topological sort on a graph. Creat

Question

Java Programming

Write a program to perform a topological sort on a graph.

Create a representation of a directed graph.

Create a Vertex class that has the value of the vertex, the indegree and a list of adjacent nodes.

Create a DirectedGraph class that is a list of Vertex objects. This is your graph.

Write a TopologicalSort class that has methods that take in a Directed graph and does a topological sort.

Your test case should use the graph representation of the following

2,3,4 4,5 6 6,7,3 4,7 (empty) 6

Explanation / Answer

import java.io.*;

import java.util.*;

public category ID3

the category to represent a knowledge purpose consisting of numAttributes values

of attributes */

class DataPoint

};

/* the category to represent a node within the decomposition tree.

*/

class TreeNode

};

TreeNode root = new TreeNode();

public int getSymbolValue(int attribute, String symbol)

return index;

}

public int []getAllValues(Vector information, int attribute) {

Vector values = new Vector();

int num = information.size();

for (int i=0; i< num; i++) {

DataPoint purpose = (DataPoint)data.elementAt(i);

String image =

(String)domains[attribute].elementAt(point.attributes[attribute] );

int index = values.indexOf(symbol);

if (index < 0)

}

int []array = new int[values.size()];

for (int i=0; i< array.length; i++) {

String image = (String)values.elementAt(i);

array = domains[attribute].indexOf(symbol);

}

values = null;

return array;

}

public Vector getSubset(Vector information, int attribute, int value) set = new Vector();

int num = information.size();

for (int i=0; i< num; i++) {

DataPoint purpose = (DataPoint)data.elementAt(i);

if (point.attributes[attribute] == value) set.addElement(point);

}

return subset;

}

public double calculateEntropy(Vector data) {

int numdata = information.size();

if (numdata == 0) come 0;

int attribute = numAttributes-1;

int numvalues = domains[attribute].size();

double total = 0;

for (int i=0; i< numvalues; i++) {

int count=0;

for (int j=0; j< numdata; j++) {

DataPoint purpose = (DataPoint)data.elementAt(j);

if (point.attributes[attribute] == i) count++;

}

double chance = one.*count/numdata;

if (count > 0) total += -probability*Math.log(probability);

}

return sum;

}

public mathematician alreadyUsedToDecompose(TreeNode node, int attribute)

if (node.parent == null) come false;

return alreadyUsedToDecompose(node.parent, attribute);

}

public void decomposeNode(TreeNode node) {

double bestEntropy=0;

boolean selected=false;

int selectedAttribute=0;

int numdata = node.data.size();

int numinputattributes = numAttributes-1;

node.entropy = calculateEntropy(node.data);

if (node.entropy == 0) return;

for (int i=0; i< numinputattributes; i++) {

int numvalues = domains.size();

if ( alreadyUsedToDecompose(node, i) ) continue;

double averageentropy = 0;

for (int j=0; j< numvalues; j++) set = getSubset(node.data, i, j);

if (subset.size() == 0) continue;

double subentropy = calculateEntropy(subset);

averageentropy += subentropy *

subset.size();

}

averageentropy = averageentropy / numdata; //

Taking the weighted average

if (selected == false) else {

if (averageentropy < bestEntropy)

}

}

if (selected == false) return;

int numvalues = domains[selectedAttribute].size();

node.decompositionAttribute = selectedAttribute;

node.children = new TreeNode [numvalues];

for (int j=0; j< numvalues; j++)

for (int j=0; j< numvalues; j++)

node.data = null;

}

public int readData(String filename) throws Exception catch ( Exception e) {

System.err.println( "Unable to open information file: " + computer file name + " " + e);

return 0;

}

BufferedReader bin = new BufferedReader(new InputStreamReader(in) );

String input;

while(true) {

input = bin.readLine();

if (input == null) {

System.err.println( "No information found within the information file: " + computer file name +

" ");

return 0;

}

if (input.startsWith("//")) continue;

if (input.equals("")) continue;

break;

}

StringTokenizer tokenizer = new StringTokenizer(input);

numAttributes = tokenizer.countTokens();

if (numAttributes <= 1) {

System.err.println( "Read line: " + input);

System.err.println( "Could not obtain the names of attributes within the

line");

System.err.println( "Expecting a minimum of one input attribute and one

output attribute");

return 0;

}

domains = new Vector[numAttributes];

for (int i=0; i < numAttributes; i++) domains = new Vector();

attributeNames = new String[numAttributes];

for (int i=0; i < numAttributes; i++)

while(true)

root.data.addElement(point);

}

bin.close();

return 1;

}

public void printTree(TreeNode node, String tab) ME = new ID3();

int standing = Pine Tree State.readData("c:\in.txt");

if (status <= 0) return;

me.createDecisionTree();

}

}

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