/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public String tree2str(TreeNode t) {
if (t==null)
return "";
if (t.left==null && t.right==null)
return t.val+"";
else if (t.left==null)
return t.val+"()"+"("+tree2str(t.right)+")";
else if(t.right==null)
return t.val+"("+tree2str(t.left)+")";
return t.val+"("+tree2str(t.left)+")"+"("+tree2str(t.right)+")";
}
}