public class BasicTree {

private class Node {

K key;

V value;

public Node(K key, V value){

this.key = key;

this.value = value;

}

}

Node root;

int curSize;

...

/**

* Produces the key sequence resulting from a pre-order tree

* traversal.

*

* @return A List of the keys in the tree in pre-order

*/

public List preOrderKeys(){

// TODO Student Code

}

/**

* Helper function for public recursive method

*/

private List preOrderKeys(Node start){

// TODO Student Code

}

}

}

Question 1: Complete the public preOrderKeys() method using a recursive algorithm. To do so, students must also implement the private version which takes a single parameter.

Question 2: Complete the public preOrderKeys() method using a non-recursive algorithm. This method may use a java.util.Stack.

Basically complete the code above. The code above is part of a preorder binary tree.