_147graph.java

import java.util.*;
public class _147graph {
    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 main(String[] args) {
        int V =5;
        @SuppressWarnings("unchecked")
        ArrayList<Edge>[] graph = new ArrayList[V];
        for (int i=0;i<V;i++){
            graph[i] = new ArrayList<>();
        }
        // 0 vertex
        graph[0].add(new Edge(0,1,5));
        // 1 vertex
        graph[1].add(new Edge(1,0,5));
        graph[1].add(new Edge(1,2,1));
        graph[1].add(new Edge(1,3,3));
        // 2 vertex
        graph[2].add(new Edge(2,1,1));
        graph[2].add(new Edge(2,3,1));
        graph[2].add(new Edge(2,4,4));
        // 3 vertex
        graph[3].add(new Edge(3,1,3));
        graph[3].add(new Edge(3,2,3));
        // 4 vertex
        graph[4].add(new Edge(4,2,2)); 

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