| 1 | class Solution { |
| 2 | public List<List<Integer>> levelOrder(TreeNode root) { |
| 3 | List<List<Integer>> list = new ArrayList<List<Integer>>(); |
| 4 | if(root==null) return list; |
| 5 | Queue<TreeNode> queue = new LinkedList<TreeNode>(); |
| 6 | queue.offer(root); |
| 7 | while(!queue.isEmpty()) |
| 8 | { |
| 9 | int nodesPresent=queue.size(); |
| 10 | List<Integer> sublist = new ArrayList<Integer>(); |
| 11 | for(int i=0;i<nodesPresent;i++) |
| 12 | { |
| 13 | if(queue.peek().left!=null) queue.offer(queue.peek().left); |
| 14 | if(queue.peek().right!=null) queue.offer(queue.peek().right); |
| 15 | sublist.add(queue.poll().val); |
| 16 | } |
| 17 | list.add(sublist); |
| 18 | } |
| 19 | return list; |
| 20 | } |
| 21 | } |