BreadthFirstSearch.cs

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
class Graph{      
private int _V;  
LinkedList<int>[] _adj;  
  
public Graph(int V) 
{ 
    _adj = new LinkedList<int>[V]; 
    for(int i = 0; i < _adj.Length; i++) 
    { 
        _adj[i] = new LinkedList<int>(); 
    } 
    _V = V; 
}   
public void AddEdge(int v, int w) 
{          
    _adj[v].AddLast(w); 
  
}   
public void BFS(int s) 
{  
    bool[] visited = new bool[_V]; 
    for(int i = 0; i < _V; i++) 
        visited[i] = false;   
    LinkedList<int> queue = new LinkedList<int>();  
    visited[s] = true; 
    queue.AddLast(s);          
  
    while(queue.Any()) 
    { 
        s = queue.First(); 
        Console.Write(s + " " ); 
        queue.RemoveFirst(); 
        LinkedList<int> list = _adj[s]; 
  
        foreach (var val in list)              
        { 
            if (!visited[val]) 
            { 
                visited[val] = true; 
                queue.AddLast(val); 
            } 
        } 
    } 
} 
static void Main(string[] args) 
{ 
    Graph g = new Graph(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); 
    Console.Write("Following is Breadth First " + 
                  "Traversal(starting from " + 
                  "vertex 2)\n"); 
    g.BFS(2); 
} 
}