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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. class Main
  6. {
  7. 	public static void main (String[] args) throws java.lang.Exception
  8. 	{
  9. 		Scanner sc = new Scanner(System.in);
  10.  
  11.  
  12. 		if (!sc.hasNextInt()) return;
  13.  
  14. 		int vertices = sc.nextInt();
  15. 		int edges = sc.nextInt();
  16.  
  17. 		// Initialize Adjacency List 
  18. 		List<List<Integer>> adj = new ArrayList<>();
  19. 		for (int i = 0; i < vertices; i++) {
  20. 			adj.add(new ArrayList<>());
  21. 		}
  22.  
  23. 		// Read all graph edges from standard input
  24. 		for (int i = 0; i < edges; i++) {
  25. 			int u = sc.nextInt();
  26. 			int v = sc.nextInt();
  27.  
  28. 			// Build an undirected graph
  29. 			adj.get(u).add(v);
  30. 			adj.get(v).add(u);
  31. 		}
  32.  
  33.  
  34. 		int startNode = sc.nextInt();
  35.  
  36. 		System.out.print("BFS Traversal starting from node " + startNode + ": ");
  37. 		bfs(startNode, vertices, adj);
  38. 	}
  39.  
  40. 	public static void bfs(int startNode, int vertices, List<List<Integer>> adj) {
  41. 		Queue<Integer> queue = new LinkedList<>();
  42. 		boolean[] visited = new boolean[vertices];
  43.  
  44.  
  45. 		visited[startNode] = true;
  46. 		queue.add(startNode);
  47.  
  48. 		while (!queue.isEmpty()) {
  49. 			int curr = queue.poll();
  50. 			System.out.print(curr + " ");
  51.  
  52.  
  53. 			for (int neighbor : adj.get(curr)) {
  54. 				if (!visited[neighbor]) {
  55. 					visited[neighbor] = true;
  56. 					queue.add(neighbor);
  57. 				}
  58. 			}
  59. 		}
  60. 		System.out.println();
  61. 	}
  62. }
  63.  
Success #stdin #stdout 0.17s 60720KB
comments (?)
stdin
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5 4
0 1
0 2
1 3
2 4
0
stdout
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BFS Traversal starting from node 0: 0 1 2 3 4
https://ideone.com/ZZnceG
language:
Java (HotSpot 12)
created:
2 hours ago
visibility:
public

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