code: /*
   * Copyright (c) 2017-2018 The Regents of the University of California
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   * 1. Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package edu.berkeley.cs.jqf.examples.trees;
  
  /**
   * @author Rohan Padhye
   */
  public class BinaryTree {
      int size = 0;
      private static class Node {
          Node left;
          Node right;
          int value;
  
          Node(int val) {
              this.value = val;
          }
      }
  
      private Node root;
  
      public void insert(int x) {
          root = insertIntoNode(x, root);
      }
  
      public int size() {
          return this.size;
      }
  
      private Node insertIntoNode(int x, Node n) {
          if (n == null) {
              size++;
              return new Node(x);
          } else if (x < n.value) {
              n.left = insertIntoNode(x, n.left);
              return n;
          } else if (x > n.value) {
              n.right = insertIntoNode(x, n.right);
              return n;
          } else {
              return n;
          }
      }
  
      public boolean contains(int x) {
          return nodeContains(root, x);
      }
  
      private boolean nodeContains(Node n, int x) {
          if (n == null) {
              return false;
          } else if (x < n.value) {
              return nodeContains(n.left, x);
          } else if (x > n.value) {
              return nodeContains(n.right, x);
          } else {
              return true;
          }
      }
  }
  