NS9Lf7 - Online Java Compiler & Debugging Tool

import java.util.*;
import java.io.*;

class Main
{

	public static void dfs(int src, List<List<Integer>> adj, int visited[], int parent[] )
	{
		visited[src]=1;
		// parent[src]=0;

			System.out.print(src+" ");
		for(int neighbour: adj.get(src))
		{
			if(visited[neighbour]==0)
			{
				parent[neighbour]=src;
				dfs(neighbour, adj,visited,parent);
			}
		}

	}
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();

        while (t-- > 0) {
            int n = sc.nextInt();
            int e = sc.nextInt();

            List<List<Integer>> adj=new ArrayList<>();
            for(int i=0;i<=n;i++)
            adj.add(new ArrayList<>());


            for (int k = 0; k < e; k++) {
                int u = sc.nextInt();
                int v = sc.nextInt();
                adj.get(u).add(v);
                adj.get(v).add(u);
            }

            int visited[]=new int[n+1];
            int level[]=new int[n+1];
            int ways[]=new int[n+1];
            int parent[]=new int[n+1];
            // parent[source]=0;

              int source =sc.nextInt();
              dfs(source,adj,visited,parent);

              	System.out.println();

              for(int i=1;i<=n;i++)
              System.out.println(i+" "+parent[i]);


    }
}
}