1. JAVA - please complete the below method ConcatenateLeaves()
/*
*/
import binarytree.*;
/**
A program that tests the concatenateLeaves() method.
*/
public class ConcatenateLeaves
{
/**
Return a string that is the concatenation of the leaves,
from the input binary tree, going from left to right.
<p>
How does this compare with an in-order, or pre-order,
or post-order traversal of the binary tree?
*/
public static <T> String concatenateLeaves(BTree<T> btree)
{
String result = "";
return result;
}
// A simple test case for concatenateLeaves().
public static void main(String[] args)
{
BTree<String> btree =
new BTreeLinked<>("#",
new BTreeLinked<>("#",
new BTreeLinked<>("mary"),
new BTreeLinked<>("had")),
new BTreeLinked<>("#",
new BTreeLinked<>("a"),
new BTreeLinked<>("#",
new BTreeLinked<>("little"),
new BTreeLinked<>("lamb"))));
String result = concatenateLeaves( btree );
System.out.println( btree );
System.out.println( result );

2. BTree2dot.btree2dot(btree, "btree");
BTree2png.btree2png("btree");
System.out.println( btree.preOrder() );
System.out.println( btree.inOrder() );
System.out.println( btree.postOrder() );
}
}