Similiar functions to traverse a binary tree

Question

I have got a binary tree

     public class Node
    {
            int value;
            Node left;
            Node right;

            public Node getLeft() {
                return left;
            }

        public Node getRight() {
            return right;
        }

        public String getValue() {
            return value;
        }
    }

And in main I have got a function to traverse it. For tree

    5
   / \
  3   7
 / \
1   2

First one creates a queue of nodes with breadth first traversal(5,3,7,1,2). Second one returns value of a node for eg. 7 for number 2 or 2 for number 4.

    private void queueOfTreaversed() {
        LinkedList<Node> queue = new LinkedList<Node>();
        if (root != null)
            queue.add(root);

        while (!queue.isEmpty()) {
            Node temp = queue.removeFirst();
            if (temp.getLeft() != null && temp.getRight() != null) {
                traversed.add(temp);    //there is a difference
                queue.add(temp.getLeft());
                queue.add(temp.getRight());
            }
        }
    }

    public int getValue(int n) {
        LinkedList<Node> queue = new LinkedList<Node>();
        if (root != null)
            queue.add(root);

        while (!queue.isEmpty() && n>0) {
            Node temp = queue.removeFirst();
            if (temp.getLeft() != null && temp.getRight() != null) {
                queue.add(temp.getLeft());
                queue.add(temp.getRight());
            }
        }
        return queue.peekFirst().getValue();  //there is a difference
    }

And I have got duplication of code that I do not how to get rid off. I use traversed in meantime and pop elements from this queue so elements will not be in this order and traversed cannot be used. Could anyone give any hint?

Answer 1

Once you have got the traversed nodes in traversed, your getValue(int n) function can actually index into traversed to get the value you want. In your getValue(int n) function, just use code like this:

if (n < traversed.size()) {
    return traversed.get(n).getValue();
}
throw new Exception("Element not existed");

To be able to use traversed, just return it in your queueOfTreaversed function.