BFS.java

import java.util.*;
public class BFS {
static class Edge {
int src;
int dest;
int wt;
public Edge(int s, int d, int w) {
this.src = s;
this.dest = d;
this.wt = w;
}
}
static void createGraph(ArrayList<Edge> graph[]) {
for(int i=0; i<graph.length; i++) {
graph[i] = new ArrayList<>();
}
graph[0].add(new Edge(0, 1, 1));
graph[0].add(new Edge(0, 2, 1));
graph[1].add(new Edge(1, 0, 1));
graph[1].add(new Edge(1, 3, 1));
graph[2].add(new Edge(2, 0, 1));

graph[2].add(new Edge(2, 4, 1));
graph[3].add(new Edge(3, 1, 1));
graph[3].add(new Edge(3, 4, 1));
graph[3].add(new Edge(3, 5, 1));
graph[4].add(new Edge(4, 2, 1));
graph[4].add(new Edge(4, 3, 1));
graph[4].add(new Edge(4, 5, 1));
graph[5].add(new Edge(5, 3, 1));
graph[5].add(new Edge(5, 4, 1));
graph[5].add(new Edge(5, 6, 1));
graph[5].add(new Edge(6, 5, 1));
}
public static void bfs(ArrayList<Edge> graph[], int V) {
boolean visited[] = new boolean[V];
Queue<Integer> q = new LinkedList<>();
q.add(0); //Source = 0
while(!q.isEmpty()) {
int curr = q.remove();
if(!visited[curr]) {
System.out.print(curr+" ");
visited[curr] = true;
for(int i=0; i<graph[curr].size(); i++) {
Edge e = graph[curr].get(i);
q.add(e.dest);
}
}
}
System.out.println();
}
public static void main(String args[]) {
/*
1 --- 3
/ | \
0 | 5 -- 6

\ | /
2 ---- 4
*/
int V = 7;
ArrayList<Edge> graph[] = new ArrayList[V];
createGraph(graph);
bfs(graph, V);
}
}