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Given the number of edges ‘E‘ and vertices ‘V‘ of a bidirectional graph. Your task is to build a graph through the adjacency list and print the adjacency list for each vertex.

Input:
The first line of input is T denoting the number of testcases.Then first line of each of the T contains two positive integer V and E where ‘V’ is the number of vertex and ‘E’ is number of edges in graph. Next, ‘E’ line contains two positive numbers showing that there is an edge between these two vertex.

Output:
For each vertex, print their connected nodes in the order you are pushing them inside the list. See the given example.

Constraints:

1 <= T <= 200
1 <= V <= 103
1 <= E = V*(V-1)

Example:

Input:

2
5 7
0 1
0 4
1 2
1 3
1 4
2 3
3 4
3 3
0 1
1 2
2 0

Output:

0-> 1-> 4
1-> 0-> 2-> 3-> 4
2-> 1-> 3
3-> 1-> 2-> 4
4-> 0-> 1-> 3
0-> 1-> 2
1-> 0-> 2
2-> 1-> 0

Explanation:

Testcase 1: Given graph has 5 nodes and 7 edges. After creating adjacency list of given graph, we have list as:
0-> 1-> 4
1-> 0-> 2-> 3-> 4
2-> 1-> 3
3-> 1-> 2-> 4
4-> 0-> 1-> 3

Solution:

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
 
int E,V,c,d;
 
int main() {
	int n;
	cin>>n;
	
	while(n--){
	   vector <int> adj[100000];
	    cin>>V>>E;

           // Inserting elements in adjacency List
	    for(int i=0;i<E;i++){
	        cin>>c>>d;
	        adj[c].push_back(d);
	        adj[d].push_back(c);
	    }

       // Printing out elements of adjacency list
	for (int v = 0; v < V; ++v) 
    { 
        cout << v ; 
        for (auto x : adj[v]) 
           cout << "-> " << x; 
        printf("\n"); 
    }   
	}

	return 0;
}

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Vishal Sharma

Currently pursuing a Computer Science degree from G.B Pant Government Engineering college, New Delhi. I am from freshybuilt team.

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