打印二叉树中距离根节点为k的所有节点

package tree;

public class Printnodesatkdistancefromroot {

	/**
	 * Given a root of a tree, and an integer k. Print all 
	 * the nodes which are at k distance from root.

For example, in the below tree, 4, 5 & 8 are at distance 2 from root.
            1
          /   \
        2      3
      /  \    /
    4     5  8 
	 * @param args
	 */
	public static void printk(TreeNode root,int k){
		if(k<0||root==null){
			return;
		}
		if(k==0){
			System.out.print(root.value+" ");
			return;
		}
		printk(root.left, k-1);
		printk(root.right, k-1);
	}
	public static void main(String[] args) {
		
		TreeNode root = new TreeNode(1);
		root.left = new TreeNode(2);
		root.right = new TreeNode(3);
		root.left.left = new TreeNode(4);
		root.left.right = new TreeNode(5);
		root.right.left = new TreeNode(8);
		printk(root, 2);

	}

}