p130.java

// Undirected and weighted graph.
// Array of ArrayList.
// Storing Source, Destination and Weight.

import java.util.*;
class adjacencyList{
    static class Edge{
        int src;
        int dest;
        int wt;
        public Edge(int s,int d,int w){
            this.src=s;
            this.dest=d;
            this.wt=w;
        }
    }
    public static void createGraph(ArrayList<Edge> graph[]){
        for(int i=0;i<graph.length;i++){
            graph[i]=new ArrayList<>();
        }
        graph[0].add(new Edge(0, 2, 2));

        graph[1].add(new Edge(1, 2, 10));
        graph[1].add(new Edge(1, 3, 0));

        graph[2].add(new Edge(2, 0, 2));
        graph[2].add(new Edge(2, 1, 10));
        graph[2].add(new Edge(2, 3, -1));

        graph[3].add(new Edge(3, 1, 0));
        graph[3].add(new Edge(3, 2, -1));
    }
    public static void main(String[] args) {
        int V=4;
        ArrayList<Edge> graph[]=new ArrayList[4];
        createGraph(graph);
        // for(int i=0;i<V;i++){
        //     for(int j=0;j<graph[i].size();j++){
        //         Edge e=graph[i].get(j);
        //         System.out.println(e.src+", "+e.dest+", "+e.wt);
        //     }
        // }

        // Print 2's neighbors
        for(int i=0;i<graph[2].size();i++){
            Edge e=graph[2].get(i);
            System.out.print(e.dest+"  ");
        }
    }
}