/**

* Definition for a binary tree node.

* public class TreeNode {

* int val;

* TreeNode left;

* TreeNode right;

* TreeNode(int x) { val = x; }

* }

*/

class Solution {

public boolean isSubtree(TreeNode s, TreeNode t)

{

String tree1 = preorder(s, true);

String tree2 = preorder(t, true);

return tree1.indexOf(tree2) >= 0;

}

public String preorder(TreeNode t, boolean left)

{

if(t == null)

{

if(left)

return "lnull";

else

return "rnull";

}

return "#" + t.val + " " + preorder(t.left, true) + " " + preorder(t.right, true);

}

}