Bfs.cpp

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

int main()
{
    int t;
    cin>>t;

    while(t--)
    {
        int n,e;
        cin>>n;
        cin>>e;

        vector<int>adj[n];

        bool vis[n] ={false};

        for(int i=0;i<e;i++)
        {
            int u,v;
            cin>>u;
            cin>>v;
            
            adj[u].push_back(v);

        }

        bfs(0,adj,vis,n);

        cout<<endl;
    }

}

void bfs(int s,vector<int>adj[],bool vis[],int n)
{
   queue<int>q;
   
   q.push(s);
   vis[s]=true;

   while(!q.empty())
   {
       int curr = q.front();
       q.pop();

       cout<<curr<<" ";

       for(int i=0;i<adj[curr].size();++i)
       
       if(vis[adj[curr][i]]==false)
       {
           q.push(adj[curr][i]);
           vis[adj[curr][i]]==true;

       }

   }

}

//all about bfs (breadth for search)