Graphs in Java

Implementasi Graph Menggunakan Java

Graphs in Java

Graph adalah cara mudah untuk menyimpan jenis data tertentu. 

Adjacency Matrix 

	class Graph {
	private int numOfNodes;
	private boolean directed;
	private boolean weighted;
	private float[][] matrix;
	/*
	This will allow us to safely add weighted graphs in our class since
	we will be able to check whether an edge exists without relying
	on specific special values (like 0)
	*/
	private boolean[][] isSetMatrix;
	// ...
	public Graph(int numOfNodes, boolean directed, boolean weighted) {
	this.directed = directed;
	this.weighted = weighted;
	this.numOfNodes = numOfNodes;
	// Simply initializes our adjacency matrix to the appropriate size
	matrix = new float[numOfNodes][numOfNodes];
	isSetMatrix = new boolean[numOfNodes][numOfNodes];
	}
	public void addEdge(int source, int destination) {
	int valueToAdd = 1;
	if (weighted) {
	valueToAdd = 0;
	}
	matrix[source][destination] = valueToAdd;
	isSetMatrix[source][destination] = true;
	if (!directed) {
	matrix[destination][source] = valueToAdd;
	isSetMatrix[destination][source] = true;
	}
	}
	public void addEdge(int source, int destination, float weight) {
	float valueToAdd = weight;
	if (!weighted) {
	valueToAdd = 1;
	}
	matrix[source][destination] = valueToAdd;
	isSetMatrix[source][destination] = true;
	if (!directed) {
	matrix[destination][source] = valueToAdd;
	isSetMatrix[destination][source] = true;
	}
	}
	public void printMatrix() {
	for (int i = 0; i < numOfNodes; i++) {
	for (int j = 0; j < numOfNodes; j++) {
	// We only want to print the values of those positions that have been marked as set
	if (isSetMatrix[i][j])
	System.out.format("%8s", String.valueOf(matrix[i][j]));
	else System.out.format("%8s", "/ ");
	}
	System.out.println();
	}
	}
	public void printEdges() {
	for (int i = 0; i < numOfNodes; i++) {
	System.out.print("Node " + i + " is connected to: ");
	for (int j = 0; j < numOfNodes; j++) {
	if (isSetMatrix[i][j]) {
	System.out.print(j + " ");
	}
	}
	System.out.println();
	}
	}
	public boolean hasEdge(int source, int destination) {
	return isSetMatrix[source][destination];
	}
	public Float getEdgeValue(int source, int destination) {
	if (!weighted || !isSetMatrix[source][destination])
	return null;
	return matrix[source][destination];
	}
	}
	public class GraphShow {
	public static void main(String[] args) {
	// Graph(numOfNodes, directed, weighted)
	Graph graph = new Graph(5, false, true);
	graph.addEdge(0, 2, 19);
	graph.addEdge(0, 3, -2);
	graph.addEdge(1, 2, 3);
	graph.addEdge(1, 3); // The default weight is 0 if weighted == true
	graph.addEdge(1, 4);
	graph.addEdge(2, 3);
	graph.addEdge(3, 4);
	graph.printMatrix();
	System.out.println();
	System.out.println();
	graph.printEdges();
	System.out.println();
	System.out.println("Does an edge from 1 to 0 exist?");
	if (graph.hasEdge(0,1)) {
	System.out.println("Yes");
	}
	else System.out.println("No");
	}
	}

view raw adjacency matrix hosted with ❤ by GitHub

Output: