BFS

#include<bits/stdc++.h>
using namespace std;

void addEdge(vector<int> adj[], int u, int v)
{
    adj[u].push_back(v);
}
void bfs(vector<int> adj[], int V, int start)
{
    //Code here
    queue<int> q;
    vector<int> vis(V,0);
    vis[start]=1;
    q.push(start);
    while(!q.empty())
    {
        int v=q.front();
        cout<<v<<" ";
        q.pop();
        for(int x:adj[v])
        {
            if(vis[x]==0)
            {
                vis[x]=1;
                q.push(x);
            }
        }
    }
}

void printGraph(vector<int> adj[], int V)
{
    for (int v = 0; v < V; ++v)
    {
        cout << "Adjacency list of vertex "
             << v << "\n";
        for (auto x : adj[v])
           cout << x <<" ";
        cout<<"\n";
    }
}
int main()
{
    int V = 4;
    vector<int> adj[V];
    addEdge(adj,0, 1);
    addEdge(adj,0, 2);
    addEdge(adj,1, 2);
    addEdge(adj,2, 0);
    addEdge(adj,2, 3);
    addEdge(adj,3, 3);
    printGraph(adj,V);
    bfs(adj, V, 2);
    return 0;
}