| 2 | { |
| 3 | //Function to return list containing elements of left view of binary tree. |
| 4 | ArrayList<Integer> leftView(Node root) |
| 5 | { |
| 6 | // Your code here |
| 7 | ArrayList<Integer> list = new ArrayList<>(); |
| 8 | if(root==null) return list; |
| 9 | Queue<Node> queue = new LinkedList<>(); |
| 10 | queue.add(root); |
| 11 | while(!queue.isEmpty()) |
| 12 | { |
| 13 | int level = queue.size(); |
| 14 | for(int i=0;i<level;i++) |
| 15 | { |
| 16 | if(queue.peek().left!=null) |
| 17 | { |
| 18 | queue.add(queue.peek().left); |
| 19 | } |
| 20 | if(queue.peek().right!=null) |
| 21 | { |
| 22 | queue.add(queue.peek().right); |
| 23 | } |
| 24 | if(i==0) |
| 25 | { |
| 26 | list.add(queue.peek().data); |
| 27 | } |
| 28 | queue.remove(); |
| 29 | } |
| 30 | } |
| 31 | return list; |
| 32 | } |
| 33 | } |