static void Main(string[] args)
{
// Creat a tree
TreeNode node1 = new TreeNode(6);
TreeNode node2 = new TreeNode(3);
TreeNode node3 = new TreeNode(8);
TreeNode node4 = new TreeNode(1);
TreeNode node5 = new TreeNode(4);
TreeNode node6 = new TreeNode(7);
TreeNode node7 = new TreeNode(9);
node1.left = node2;
node1.right = node3;
node2.left = node4;
node2.right = node5;
//node3.left = node6;
//node3.right = node7;
SolutionNK s = new SolutionNK();
var head = s.PrintFromTopToBottom(node1);
Console.ReadKey();
}
public int[] LevelOrder(TreeNode root)
{
SolutionNK snk = new SolutionNK();
return(snk.PrintFromTopToBottom(root).ToArray());
}