jgs CSE 205 Object-Oriented Programming and Data Structures Lecture 21: Binary Tree Dr. Javier Gonzalez-Sanchez [email protected] javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 2 jgs Quiz 05 § Open Today. § You have a week to work § A 30 minutes Quiz about data structures (including Trees) 

jgs Nuts and bolts of Binary Trees Nodes 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 4 jgs What is the problem with arrays? 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 5 jgs I introduce you a List, a Linked List 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 6 jgs What about this? 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 7 jgs Binary Tree § A non-linear data structure § where each node can have 2 children at most. § keep the tree sorted 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 8 jgs Node class Node { public int value; public Node left public Node right; Node(int value){ value = value; left = null; right = null; } } 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 9 jgs Tree | insert public class Tree { public void insert(Node node, int value) { if (value < node.value) { if (node.left != null) { insert(node.left, value); } else { System.out.println(" Inserted to left"); node.left = new Node(value); } } else if (value > node.value) { if (node.right != null) { insert(node.right, value); } else { System.out.println(" Inserted to right "); node.right = new Node(value); } } } 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 10 jgs Tree | Example public static void main(String args[]) { Tree tree = new Tree(); Node root = new Node(5); tree.insert(root, 2); tree.insert(root, 4); tree.insert(root, 8); tree.insert(root, 6); tree.insert(root, 7); tree.insert(root, 3); tree.insert(root, 9); tree.traverseLevelOrder(); } } 

jgs Nuts and bolts of Binary Trees Traverse 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 12 jgs Tree | Traverse In Order public void traverseInOrder(Node node) { if (node != null) { traverseInOrder(node.left); System.out.print(" " + node.value); traverseInOrder(node.right); } } 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 13 jgs Tree | Traverse In Order 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 14 jgs Tree | Traverse Pre Order public void traverseInOrder(Node node) { if (node != null) { System.out.print(" " + node.value); traverseInOrder(node.left); traverseInOrder(node.right); } } 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 15 jgs Tree | Traverse Pre Order 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 16 jgs Tree | Traverse Post Order public void traverseInOrder(Node node) { if (node != null) { traverseInOrder(node.left); traverseInOrder(node.right); System.out.print(" " + node.value); } } 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 17 jgs Tree | Traverse Post Order 

Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 30 jgs Questions 

jgs CSE 205 Object-Oriented Programming and Data Structures Javier Gonzalez-Sanchez, Ph.D. [email protected] Fall 2021 Copyright. These slides can only be used as study material for the class CSE205 at Arizona State University. They cannot be distributed or used for another purpose.