Print LO-T

PrintLevelOrder.java

package ws.abhis.interviews.amazon;

import junit.framework.TestCase;
import ws.abhis.interviews.TreeNode;

import java.util.LinkedList;
import java.util.Queue;

/**
 * Level order traversal and print each level in one line.
 */
public class PrintLevelOrder extends TestCase {
    public void solution(TreeNode root) {
        if (root == null)
            return;

        Queue<TreeNode> queue = new LinkedList<>();
        int current = 1, next = 0;
        queue.add(root);

        while (!queue.isEmpty()) {
            TreeNode n = queue.remove();
            System.out.print(n.val + "\t");
            current = current-1;

            if (n.left != null) {
                queue.add(n.left);
                next = next+1;
            }
            if (n.right != null) {
                queue.add(n.right);
                next = next+1;
            }

            if (current == 0) {
                current = next;
                next = 0;
                System.out.println();
            }
        }
    }

    public void testOne() {
        TreeNode one = new TreeNode(1);
        TreeNode two = new TreeNode(2);
        TreeNode three = new TreeNode(3);
        TreeNode four = new TreeNode(4);
        TreeNode five = new TreeNode(5);
        TreeNode six = new TreeNode(6);
        TreeNode seven = new TreeNode(7);

        one.left = two; one.right = three;
        two.left = four; two.right = five;
        three.left = six; three.right = seven;

        solution(one);
    }
}