Graphs/BFS at master · KnowledgeCenterYoutube/Graphs · GitHub

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Breadth First Search(BFS) traversal
Detailed Explanation available here: https://youtu.be/6J50_2SD0C8

// C++

#include <iostream>
#include <queue>
using namespace std;

class Graph{
	int m_V;
  	vector<vector<int>> m_adj;
public:
  	Graph(int V): m_V(V), m_adj(V){}
  	void addEdge(int u, int v){
    		m_adj[u].push_back(v);
  	}
  	void BFS(int s){
    		queue<int> Q;
    		vector<bool> visited(m_V, false);
    		Q.push(s);
    		visited[s] = true;
    		while(!Q.empty()){
      			int v = Q.front();
      			Q.pop();
      			cout << v << "  ";
      			for(int u : m_adj[v])
        			if(!visited[u]){
        				Q.push(u);
        				visited[u] = true;
        			}
    		}
  	}
};

int main(){
  	Graph G(5);
  	G.addEdge(0,1);
  	G.addEdge(0,3);
  	G.addEdge(1,2);
  	G.addEdge(3,2);
  	G.addEdge(3,4);
  	G.BFS(0);

  return 0;
}

// Java
import java.util.*;
import java.lang.*;
import java.io.*;

class Graph {
	private int m_V;
	private List<Integer>[] m_adj;
	Graph(int v){
		m_V = v;
		m_adj = new LinkedList[v];
		for(int i = 0; i < v; ++i)
			m_adj[i] = new LinkedList<Integer>();
	}

	public void addEdge(int u, int v){
		m_adj[u].add(v);
	}

	public void BFS(int s){
    	LinkedList<Integer> Q = new LinkedList();
    	boolean[] visited = new boolean[m_V];
    	Q.add(s);
    	visited[s] = true;
    	while(!Q.isEmpty()){
    		int v = Q.poll();
    		System.out.println(v+" ");
    		for(int u : m_adj[v]){
        		if(!visited[u]){
        			Q.add(u);
        			visited[u] = true;
        		}
        	}
    	}
    }

	public static void main (String[] args) throws java.lang.Exception{
		Graph G = new Graph(5);
		G.addEdge(0,1);
		G.addEdge(0,3);
		G.addEdge(1,2);
		G.addEdge(3,2);
		G.addEdge(3,4);
		G.BFS(0);
	}
}


# Python3

class Graph:
	def __init__(self, v):
		self.m_V = v
		self.m_adj = [[] for i in range(v)]

	def addEdge(self, u, v):
		self.m_adj[u].append(v)

	def BFS(self, s):
		Q = []
		visited = [False]*self.m_V
		Q.append(s)
		visited[s] = True
		while len(Q) > 0:
			v = Q.pop(0)
			print(f'{v} ')
			for u in self.m_adj[v]:
				if not visited[u]:
					Q.append(u)
					visited[u] = True

G = Graph(5)
G.addEdge(0,1)
G.addEdge(0,3)
G.addEdge(1,2)
G.addEdge(3,2)
G.addEdge(3,4)
G.BFS(0)