import java.util.ArrayList;

import java.util.Arrays;

public class SerializeAndDeserialize_297 {

class TreeNode {

int val;

TreeNode left;

TreeNode right;

TreeNode(int val) {

this.val = val;

}

}

// Encodes a tree to a single string.

public String serialize(TreeNode root) {

return rSerialize(root, "");

}

private String rSerialize(TreeNode root, String str) {

if (root == null) {

return str += "None,";

}

str += root.val + ",";

str = rSerialize(root.left, str);

str = rSerialize(root.right, str);

return str;

}

// Decodes your encoded data to tree.

public TreeNode deserialize(String data) {

String[] strArr = data.split(",");

ArrayList<String> list = new ArrayList<>(Arrays.asList(strArr));

return rDeserialize(list);

}

private TreeNode rDeserialize(ArrayList<String> list) {

if ("None".equals(list.get(0))) {

list.remove(0);

return null;

}

TreeNode root = new TreeNode(Integer.valueOf(list.get(0)));

list.remove(0);

root.left = rDeserialize(list);

root.right = rDeserialize(list);

return root;

}

}