Mikhail Spitsin programmerr47

## SampleTest.kt
interface One {
    val havePossibility: Boolean
    fun invoke()
}

interface Two {
    fun invoke()
}

class Sample(

## Depth-First-Iterator
//sample Node.class of three
class Node {
	Object data;
	Node left;
	Node right;

	public boolean isLeaf() {
		return left == null && right == null;
	}
}
	interface One {
	val havePossibility: Boolean
	fun invoke()
	}

	interface Two {
	fun invoke()
	}

	class Sample(
	//sample Node.class of three
	class Node {
	Object data;
	Node left;
	Node right;

	public boolean isLeaf() {
	return left == null && right == null;
	}
	}