09.Prim'sAlgorithm.java

/*
9. Find Minimum Cost Spanning Tree of a given connected undirected graph using Prim's algorithm.
*/

import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("Enter Number of Vertices");
        int n = scanner.nextInt();
        int[][] costMatrix = new int[n][n];
        boolean[] visited = new boolean[n];

        System.out.println("Enter Cost Adjacency Matrix");
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
                costMatrix[i][j] = scanner.nextInt();

        for (int i = 0; i < n; i++)
            visited[i] = false;

        System.out.println("Enter Source Vertex");
        int srcVertex = scanner.nextInt();

        visited[srcVertex - 1] = true;

        int source = 0, cost = 0, target = 0;
        System.out.print("Edges: ");
        
        for (int i = 1; i < n; i++) {
            int min = Integer.MAX_VALUE;

            for (int j = 0; j < n; j++) {
                if (visited[j]) {

                    for (int k = 0; k < n; k++) {
                        if (!visited[k] && min > costMatrix[j][k]) {
                            min = costMatrix[j][k];
                            source = j;
                            target = k;
                        }
                    }
                }
            }
            visited[target] = true;
            System.out.print("(" + (source + 1) + "," + (target + 1) + ")");
            cost += min;
        }
        System.out.println("\nMinimum cost of Spanning Tree: " + cost);
    }
}