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  1. import java.util.LinkedList;
  2. class Node {
  3. 	public Node left;
  4. 	public int data;
  5. 	public Node right;
  6.  
  7. 	public Node(int val) {
  8. 		this.data = val;
  9. 	}
  10.  
  11. 	@Override
  12. 	public String toString() {
  13. 		return this.data + "";
  14. 	}
  15. }
  16.  
  17.  class LeftView {
  18.  
  19. 		public void leftViewQueue(Node root) {
  20.  
  21. 		boolean isFirstNode = false;
  22. 		LinkedList<Node> queue = new LinkedList<Node>();
  23.  
  24. 		queue.addLast(root);  //enqueue
  25. 		queue.addLast(null);  //enqueue
  26.  
  27. 		System.out.print(root.data + "\t");
  28. 		while (!queue.isEmpty()) {
  29. 			Node poped = queue.removeFirst(); //dequeue  
  30.  
  31. 			if (poped == null) {     
  32. 				isFirstNode = true;  //current level processed , push null for next level
  33. 				queue.addLast(null);
  34. 			} 
  35. 			else {
  36.  
  37. 				if(isFirstNode == true)
  38. 				{
  39. 					System.out.print(poped.data + "\t");  // Print first Node 
  40. 				    isFirstNode = false;       //and set flag to be false until next null encountered
  41. 				}
  42.  
  43. 				if (poped.left != null)
  44. 				queue.addLast(poped.left);
  45. 				if (poped.right != null)
  46. 				queue.addLast(poped.right);
  47. 			}
  48. 		}
  49. 	}
  50.  
  51. 	public static void main(String[] args) {
  52. 		Node root = new Node(1);
  53. 		root.left = new Node(2);
  54. 		root.left.left = new Node(4);
  55. 		root.left.right = new Node(5);
  56. 		root.left.right.left = new Node(7);
  57. 		root.left.right.right = new Node(8);
  58. 		root.left.right.left.left = new Node(9);
  59.  
  60. 		root.right = new Node(3);
  61. 		root.right.left = new Node(6);
  62. 		root.right.right = new Node(7);
  63.  
  64. 		LeftView obj = new LeftView();
  65.  
  66. 		obj.leftViewQueue(root);
  67. 	}
  68. }
  69.  
Runtime error #stdin #stdout #stderr 4.98s 380224KB
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stdin
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Standard input is empty
stdout
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1	2	4	7	9
stderr
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/spoj/java_run: line 9: 10794 CPU time limit exceeded /opt/$VER/bin/java -client -Xmx256M -Xms16M -Xbatch -Dfile.encoding=UTF-8 -jar tested.zip
https://ideone.com/veAh01
language:
Java (12.0.1)
created:
10 years ago
visibility:
secret

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