Dijkstra.c

import java.util.*;

public class DijkstraAlgorithm {
    private static final int NO_PARENT = -1;

    private static void dijkstra(int[][] adjacencyMatrix, int startVertex) {
        int nVertices = adjacencyMatrix[0].length;
        int[] shortestDistances = new int[nVertices];
        boolean[] added = new boolean[nVertices];

        for (int vertexIndex = 0; vertexIndex < nVertices; vertexIndex++) {
            shortestDistances[vertexIndex] = Integer.MAX_VALUE;
            added[vertexIndex] = false;
        }

        shortestDistances[startVertex] = 0;
        int[] parents = new int[nVertices];
        parents[startVertex] = NO_PARENT;

        for (int i = 1; i < nVertices; i++) {
            int nearestVertex = -1;
            int shortestDistance = Integer.MAX_VALUE;
            for (int vertexIndex = 0; vertexIndex < nVertices; vertexIndex++) {
                if (!added[vertexIndex] && shortestDistances[vertexIndex] < shortestDistance) {
                    nearestVertex = vertexIndex;
                    shortestDistance = shortestDistances[vertexIndex];
                }
            }

            added[nearestVertex] = true;

            for (int vertexIndex = 0; vertexIndex < nVertices; vertexIndex++) {
                int edgeDistance = adjacencyMatrix[nearestVertex][vertexIndex];

                if (edgeDistance > 0 && ((shortestDistance + edgeDistance) < shortestDistances[vertexIndex])) {
                    parents[vertexIndex] = nearestVertex;
                    shortestDistances[vertexIndex] = shortestDistance + edgeDistance;
                }
            }
        }

        printSolution(startVertex, shortestDistances, parents);
    }

    private static void printSolution(int startVertex, int[] distances, int[] parents) {
        int nVertices = distances.length;
        System.out.print("Vertex\t Distance\tPath");

        for (int vertexIndex = 0; vertexIndex < nVertices; vertexIndex++) {
            if (vertexIndex != startVertex) {
                System.out.print("\n" + startVertex + " -> ");
                System.out.print(vertexIndex + " \t\t ");
                System.out.print(distances[vertexIndex] + "\t\t");
                printPath(vertexIndex, parents);
            }
        }
    }

    private static void printPath(int currentVertex, int[] parents) {
        if (currentVertex == NO_PARENT) {
            return;
        }
        printPath(parents[currentVertex], parents);
        System.out.print(currentVertex + " ");
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the number of vertices: ");
        int n = sc.nextInt();
        int[][] graph = new int[n][n];
        System.out.println("Enter the adjacency matrix: ");
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                graph[i][j] = sc.nextInt();
            }
        }
        System.out.println("Enter the starting vertex: ");
        int startVertex = sc.nextInt();
        dijkstra(graph, startVertex);
        sc.close();
    }
}