public class BinaryTree<E> {
    protected TreeNode root;

    public BinaryTree() {
        this.root = null;
    }

    public void add(E value) {
        this.root = this.add(this.root, value);
    }
    private TreeNode<E> add(TreeNode<E> current, E value) {
        if (current == null) {
            current = new TreeNode<E>(value, null, null);
        }
        else if (current.getLeft() == null) {
            current.setLeft(new TreeNode<E>(value, null, null));
        }
        else if (current.getRight() == null) {
            current.setRight(new TreeNode<E>(value, null, null));
        }
        else if (Math.random() < 0.5) {
            current.setLeft(this.add(current.getLeft(), value));
        }
        else {
            current.setRight(this.add(current.getRight(), value));
        }
        return current;
    }


    public int size() {
        return this.size(this.root);
    }
    private int size(TreeNode<E> current) {
        if (current == null) {
            return 0;
        }
        else {
            return this.size(current.getLeft()) +
                   this.size(current.getRight()) + 1;
        }
    }


    public boolean contains(E value) {
        return this.contains(this.root, value);
    }
    private  boolean contains(TreeNode<E> current, E value) {
        if (current == null) {
            return false;
        }
        else {
            return value.equals(current.getData()) ||
                   this.contains(current.getLeft(), value) ||
                   this.contains(current.getRight(), value);
        }
    }


    public boolean remove(E value) {
        if (!this.contains(value)) {
            return false;
        }
        else {
            this.root = this.remove(this.root, value);
            return true;
        }
    }
    private TreeNode<E> remove(TreeNode<E> current, E value) {
        if (value.equals(current.getData())) {
            if (current.getLeft() == null) {
                current = current.getRight();
            }
            else {
                TreeNode<E> righty = current.getLeft();
                while (righty.getRight() != null) {
                    righty = righty.getRight();
                }
                current.setData(righty.getData());
                current.setLeft(this.remove(current.getLeft(), current.getData()));
            }
        }
        else if (this.contains(current.getLeft(), value)) {
            current.setLeft(this.remove(current.getLeft(), value));
        }
        else {
            current.setRight(this.remove(current.getRight(), value));
        }
        return current;
    }


    public String toString() {
        if (this.root == null) {
            return "[]";
        }

        String recStr = this.toString(this.root);
        return "[" + recStr.substring(0,recStr.length()-1) + "]";
    }
    private String toString(TreeNode<E> current) {
        if (current ==  null) {
            return "";
        }

        return this.toString(current.getLeft()) +
               current.getData().toString() + "," +
               this.toString(current.getRight());
    }


    public static void main(String[] args) {
        BinaryTree<Integer> tree = new BinaryTree<Integer>();
        tree.add(7);
        tree.add(2);
        tree.add(12);
        tree.add(1);
        tree.add(5);
        tree.add(6);
        tree.add(99);
        tree.add(88);

        System.out.println(tree);
        System.out.println("size = " + tree.size());
        System.out.println(tree.contains(2) + " " + tree.contains(5)
                                            + " " + tree.contains(8));

        tree.remove(2);
        System.out.println(tree);
        System.out.println("size = " + tree.size());
        System.out.println(tree.contains(2) + " " + tree.contains(5)
                                            + " " + tree.contains(8));

    }
}