Data Structures and Algorithms Trees 
CRICOS Provide Code: 00301J Page 1 of 3 
 
Note: 
• DSATreeNode has already been written for you, but you’ll need to understand
 and test it. 
• The code for find() was already implemented for you - insert() and 
delete() are very similar. The methods must all use the recursive approaches 
and pseudocode from the lecture slides. 
• You may want to leave delete() until you finish the rest of the practical 
and then come back to it. 
Trees 
 
Updated: 20th July, 2023 
 
Aims 
• To implement a binary tree. 
• To traverse a tree. 
 
Before the Practical 
• Read this practical sheet fully before starting. 
• Ensure you have completed either Practical 3 or Practical 4. 
 
Activities 
 
1. Binary Search Tree Implementation 
Following the lecture slides as a guide, implement a Binary Search Tree using a 
DSATreeNode and DSABinarySearchTree class. 
 
2. Implement Additional Methods 
The lecture slides described the approach for doing min(), max() and height(). Implement
 each of these operations in DSABinarySearchTree. Data Structures and Algorithms Trees 
CRICOS Provide Code: 00301J Page 2 of 3 
  
Note: Approaches can include comparing left and right heights or comparing 
potential and actual leaf nodes. 
Note: You may want to export the output of each traversal method as a queue 
or linked list, which can then be iterated over to display the contents. 
 
Now consider how you would give a percentage score for how balanced the tree is. 
Implement this approach as a new method called balance(). 
 
3. Implement Traversal Methods 
The lecture slides described the approach for doing inorder(), preorder() and postorder() 
traversals of a tree. Add recursive implementations of these algorithms inside 
DSABinarySearchTree to output the traversed tree. 
 
4. Interactive Menu for DSABinarySearchTree 
Setup an interactive menu system to explore building a binary tree from scratch. 
Include at least the following options: 
(a) Add node 
(b) Delete node 
(c) Display the tree - ask the user if they want inorder, preorder or postorder traversal

Submission Deliverable 
• Your code are due 2 weeks from your current tutorial session. 
– You will demonstrate your work to your tutors during that session 
– If you have completed the practical earlier, you can demonstrate your work 
during the next session 
• You must submit your code and any test data that you have been using electronically
via Blackboard under the Assessments section before your demonstration. 
– Java students, please do not submit the *.class files Data Structures and Algorithms Trees 
CRICOS Provide Code: 00301J Page 3 of 3 
 
Marking Guide 
Your submission will be marked as follows: 
• [6] Your DSABinarySearchTree and DSATreeNode are implemented correctly. 
• [4] You have implemented and tested your methods for min(), max(), height() 
and balance(). 
• [6] You have implemented and can demonstrate your methods for inorder(), 
preorder() and postorder(). 
• [4] You have an interactive menu for the tree operations. 

End of Worksheet 

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