This Java program,to find the single source shortest path in directed acyclic graph by Dijkstra’s algorithm.Dijkstra’s algorithm is a graph search algorithm that solves the single-source shortest path problem for a graph with non-negative edge path costs, producing a shortest path tree.
Here is the source code of the Java program to find the single source shortest path in directed acyclic graph. The Java program is successfully compiled and run on a Linux system. The program output is also shown below.
import java.util.InputMismatchException; import java.util.Scanner; public class DijkstraShortestPath { private boolean settled[]; private boolean unsettled[]; private int distances[]; private int adjacencymatrix[][]; private int numberofvertices; public DijkstraShortestPath(int numberofvertices) { this.numberofvertices = numberofvertices; this.settled = new boolean[numberofvertices + 1]; this.unsettled = new boolean[numberofvertices + 1]; this.distances = new int[numberofvertices + 1]; this.adjacencymatrix = new int[numberofvertices + 1][numberofvertices + 1]; } public void dijkstraShortestPath(int source, int adjacencymatrix[][]) { int evaluationnode; for (int vertex = 1; vertex <= numberofvertices; vertex++) { distances[vertex] = Integer.MAX_VALUE; } for (int sourcevertex = 1; sourcevertex <= numberofvertices; sourcevertex++) { for (int destinationvertex = 1; destinationvertex <= numberofvertices; destinationvertex++) { this.adjacencymatrix[sourcevertex][destinationvertex] = adjacencymatrix[sourcevertex][destinationvertex]; } } unsettled = true; distances = 0; while (getUnsettledCount(unsettled) != 0) { evaluationnode = getNodeWithMinimumDistanceFromUnsettled(unsettled); unsettled[evaluationnode] = false; settled[evaluationnode] = true; evaluateNeighbours(evaluationnode); } } public int getUnsettledCount(boolean unsettled[]) { int count = 0; for (int vertex = 1; vertex <= numberofvertices; vertex++) { if (unsettled[vertex] == true) { count++; } } return count; } public int getNodeWithMinimumDistanceFromUnsettled(boolean unsettled[]) { int min = Integer.MAX_VALUE; int node = 0; for (int vertex = 1; vertex <= numberofvertices; vertex++) { if (unsettled[vertex] == true && distances[vertex] < min) { node = vertex; min = distances[vertex]; } } return node; } public void evaluateNeighbours(int evaluationNode) { int edgeDistance = -1; int newDistance = -1; for (int destinationNode = 1; destinationNode <= numberofvertices; destinationNode++) { if (settled[destinationNode] == false) { if (adjacencymatrix[evaluationNode][destinationNode] != Integer.MAX_VALUE) { edgeDistance = adjacencymatrix[evaluationNode][destinationNode]; newDistance = distances[evaluationNode] + edgeDistance; if (newDistance < distances[destinationNode]) { distances[destinationNode] = newDistance; } unsettled[destinationNode] = true; } } } } public static void main(String... arg) { int adjacency_matrix[][]; int number_of_vertices; int source = 0; Scanner scan = new Scanner(System.in); try { System.out.println("Enter the number of vertices"); number_of_vertices = scan.nextInt(); adjacency_matrix = new int[number_of_vertices + 1][number_of_vertices + 1]; System.out.println("Enter the Weighted Matrix for the graph"); for (int i = 1; i <= number_of_vertices; i++) { for (int j = 1; j <= number_of_vertices; j++) { adjacency_matrix[i][j] = scan.nextInt(); if (i == j) { adjacency_matrix[i][j] = 0; continue; } if (adjacency_matrix[i][j] == 0) { adjacency_matrix[i][j] = Integer.MAX_VALUE; } } } System.out.println("Enter the source "); source = scan.nextInt(); DijkstraShortestPath dijkstrasAlgorithm = new DijkstraShortestPath(number_of_vertices); dijkstrasAlgorithm.dijkstraShortestPath(source, adjacency_matrix); System.out.println("The Shorted Path to all nodes are "); for (int i = 1; i <= dijkstrasAlgorithm.distances.length - 1; i++) { System.out.println(source + " to " + i + " is "+ dijkstrasAlgorithm.distances[i]); } } catch (InputMismatchException inputMismatch) { System.out.println("Wrong Input Format"); } scan.close(); } }
$javac DijkstraShortestPath.java $java DijkstraShortestPath Enter the number of vertices 5 Enter the Weighted Matrix for the graph 0 9 6 5 3 0 0 0 0 0 0 2 0 4 0 0 0 0 0 0 0 0 0 0 0 Enter the source 1 The Shorted Path to all nodes are 1 to 1 is 0 1 to 2 is 8 1 to 3 is 6 1 to 4 is 5 1 to 5 is 3
Related posts:
Spring JDBC
Introduction to Spring Data JPA
Java Program to Implement PriorityBlockingQueue API
The Registration Process With Spring Security
A Guide to JPA with Spring
Java 8 StringJoiner
Java Program to Implement ConcurrentLinkedQueue API
Tạo ứng dụng Java RESTful Client không sử dụng 3rd party libraries
Merging Two Maps with Java 8
Hướng dẫn Java Design Pattern – Decorator
A Quick Guide to Using Keycloak with Spring Boot
Java Program to Represent Graph Using Incidence List
Java Program to Compute the Area of a Triangle Using Determinants
Exploring the Spring Boot TestRestTemplate
Supplier trong Java 8
Working with Kotlin and JPA
Java Program to Implement Stein GCD Algorithm
Java Program to Implement Gabow Algorithm
Java Program to Find the Longest Path in a DAG
Convert Character Array to String in Java
Daemon Threads in Java
Java Program to Implement the String Search Algorithm for Short Text Sizes
Spring Security and OpenID Connect
Flattening Nested Collections in Java
Service Registration with Eureka
Java Program to Check the Connectivity of Graph Using DFS
JUnit 5 @Test Annotation
So sánh HashMap và HashSet trong Java
Java 8 and Infinite Streams
Spring Data Java 8 Support
Từ khóa static và final trong java
Spring Boot - Google OAuth2 Sign-In