input_list.java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

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

        // Input number of vertices
        System.out.print("Enter the number of vertices: ");
        int numberOfVertices = scanner.nextInt();

        // Initialize the adjacency list
        List<List<Integer>> adjacencyList = new ArrayList<>();
        for (int i = 0; i < numberOfVertices; i++) {
            adjacencyList.add(new ArrayList<>());
        }

        // Input number of edges
        System.out.print("Enter the number of edges: ");
        int numberOfEdges = scanner.nextInt();

        // Input edges
        System.out.println("Enter the edges (startVertex endVertex):");
        for (int i = 0; i < numberOfEdges; i++) {
            int startVertex = scanner.nextInt();
            int endVertex = scanner.nextInt();

            // Add edge to adjacency list
            adjacencyList.get(startVertex).add(endVertex);
            adjacencyList.get(endVertex).add(startVertex); // Uncomment for undirected graph
        }

        // Print the adjacency list
        System.out.println("\nAdjacency List:");
        for (int i = 0; i < numberOfVertices; i++) {
            System.out.print(i + ": ");
            for (int neighbor : adjacencyList.get(i)) {
                System.out.print(neighbor + " ");
            }
            System.out.println();
        }
    }
}