Java Program for Dijkstra’s Algorithm with Path Printing
import java.util.Scanner; //Scanner Function to take in the Input Values public class Dijkstra { static Scanner scan; // scan is a Scanner Object public static void main(String[] args) { int [] preD = new int [ 5 ]; int min = 999 , nextNode = 0 ; // min holds the minimum value, nextNode holds the value for the next node. scan = new Scanner(System.in); int [] distance = new int [ 5 ]; // the distance matrix int [][] matrix = new int [ 5 ][ 5 ]; // the actual matrix int [] visited = new int [ 5 ]; // the visited array System.out.println( "Enter the cost matrix" ); for ( int i = 0 ; i < distance.length; i++) { visited[i] = 0 ; //initialize visited array to zeros preD[i] = 0 ; for ( int j = 0 ; j < distance.length; j++) { matrix[i][j] = scan.nextInt(); //fill the matrix if (matrix[i][j]== 0 ) matrix[i][j] = 999 ; // make the zeros as 999 } } distance = matrix[ 0 ]; //initialize the distance array visited[ 0 ] = 1 ; //set the source node as visited distance[ 0 ] = 0 ; //set the distance from source to source to zero which is the starting point for ( int counter = 0 ; counter < 5 ; counter++) { min = 999 ; for ( int i = 0 ; i < 5 ; i++) { if (min > distance[i] && visited[i]!= 1 ) { min = distance[i]; nextNode = i; } } visited[nextNode] = 1 ; for ( int i = 0 ; i < 5 ; i++) { if (visited[i]!= 1 ) { if (min+matrix[nextNode][i] < distance[i]) { distance[i] = min+matrix[nextNode][i]; preD[i] = nextNode; } } } } for ( int i = 0 ; i < 5 ; i++) System.out.print( "|" + distance[i]); System.out.println( "|" ); int j; for ( int i = 0 ; i < 5 ; i++) { if (i!= 0 ) { System.out.print( "Path = " + i); j = i; do { j = preD[j]; System.out.print( " <- " + j); } while (j != 0 ); } System.out.println(); } } } |
This program is contributed by Raj Miglani. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above