Implement the following method in BST.java that returns the keys in level order (in order of their distance from the root, with nodes on each level in order from left to right). Hint : Study keys(..) method in term of how to return an iterable instance. Use a Queue for traversal. public Iterable KeysInLevelOrder()

Code provided for use:

package edu.csus.csc130.chapter3; /** * Left leaning red-black BST implementation * With many method implementation similar to BST omitted */ public class RedBlackBST, Value> { private static final boolean RED = true; private static final boolean BLACK = false; private Node root; private class Node { Key key; // key Value val; // associated data Node left, right; // subtrees int n; // # nodes in this subtree boolean color; // color of link from parent to this node Node(Key key, Value val, int n, boolean color) { this.key = key; this.val = val; this.n = n; this.color = color; } } private boolean isRed(Node x) { if (x == null) return false; return x.color == RED; } // get the number of nodes rooted at Node node private int size(Node node) { return (node == null ? 0: node.n); } //make a right-leaning link lean to the left Node rotateLeft(Node h) { Node x = h.right; h.right = x.left; x.left = h; x.color = h.color; h.color = RED; x.n = h.n; h.n = 1 + size(h.left) + size(h.right); return x; } // make a left-leaning link lean to the right Node rotateRight(Node h) { Node x = h.left; h.left = x.right; x.right = h; x.color = h.color; h.color = RED; x.n = h.n; h.n = 1 + size(h.left) + size(h.right); return x; } // flip colors to split a 4-node void flipColors(Node h) { h.color = RED; h.left.color = BLACK; h.right.color = BLACK; } //Search for key. Update value if found; grow table if new. public void put(Key key, Value val) { root = put(root, key, val); root.color = BLACK; } private Node put(Node h, Key key, Value val) { if (h == null) // Do standard insert, with red link to parent. return new Node(key, val, 1, RED); int cmp = key.compareTo(h.key); if (cmp < 0) h.left = put(h.left, key, val); else if (cmp > 0) h.right = put(h.right, key, val); else h.val = val; if (isRed(h.right) && !isRed(h.left)) h = rotateLeft(h); if (isRed(h.left) && isRed(h.left.left)) h = rotateRight(h); if (isRed(h.left) && isRed(h.right)) flipColors(h); h.n = size(h.left) + size(h.right) + 1; return h; } }