Bfs

#include<bits/stdc++.h>

using namespace std;

class Graph

{

int V;

vector<list<int>> adj;

public:

Graph(int V); // Constructor

void addEdge(int v, int w);

void BFS(int s);

};

Graph::Graph(int V)

{

this->V = V;

adj.resize(V);

}

void Graph::addEdge(int v, int w)

{

adj[v].push_back(w);

}

void Graph::BFS(int s)

{

vector<bool> visited;

visited.resize(V,false);

list<int> queue;

visited[s] = true;

queue.push_back(s);

while(!queue.empty())

{

s = queue.front();

cout << s << " ";

queue.pop_front();

for (auto adjecent: adj[s])

{

if (!visited[adjecent])

{

visited[adjecent] = true;

queue.push_back(adjecent);

}

}

}

}

int main(){

Graph g(4);

g.addEdge(0, 1);

g.addEdge(0, 2);

g.addEdge(1, 2);

g.addEdge(2, 0);

g.addEdge(2, 3);

g.addEdge(3, 3);

cout << "Following is Breadth First Traversal "

<< "(starting from vertex 2) \n";

g.BFS(2);

return 0;

}