Codec.java

public class Codec
{    // Encodes a tree to a single string.    public String serialize(TreeNode root)    {        if (root == null)
    //         return null;        Queue<TreeNode> queue = new LinkedList<>();        StringBuilder sb = new
//         StringBuilder();        queue.add(root);        while (!queue.isEmpty())        {            TreeNode node
//         = queue.poll();            sb.append(node.val).append(",");            if (node.left != null)
//         queue.add(node.left);            if (node.right != null)                queue.add(node.right);        }
//         return sb.toString();    }    public TreeNode deserialize(String data)    {        if (data == null)
//         return null;        String[] nodeValues = data.split(",");        Queue<Integer> queue = new LinkedList<>
//         ();        for (String str : nodeValues)        {            queue.offer(Integer.parseInt(str));        }
//         return getNode(queue);    }    private TreeNode getNode(Queue<Integer> queue)    {        if (queue
//         .isEmpty())            return null;        int rootVal = queue.poll();        TreeNode root = new TreeNode
//         (rootVal);        Queue<Integer> leftQueue = new LinkedList<>();        Queue<Integer> rightQueue = new
//         LinkedList<>();        while (!queue.isEmpty())        {            if (queue.peek() < rootVal)
//         {                leftQueue.offer(queue.poll());            }            else            {
//         rightQueue.offer(queue.poll());            }        }        root.left = getNode(leftQueue);        root
//         .right = getNode(rightQueue);        return root;    }    public static class TreeNode    {        int
//         val;        TreeNode left;        TreeNode right;        TreeNode(int x)        {            val = x;
//         }    }}