2 introduction to data structure

using Java

2015

Data Structure Prepared by: Mahmoud Rafeek Al-farra

in Java

2. Introduction to data structure

mfarra.cst.ps www.fb.com/MahmoudRFarra

Contents

Big - Oh notation

Generic programming

Collection Classes

Applications of data structure

What is data structure ?

What is data structure ?mfarra.cst.ps www.fb.com/MahmoudRFarra

Data Structure: Abstract way to organize information. A collection of basic data types.

Algorithm: Abstract way to perform computation tasks.

What is data structure ?mfarra.cst.ps www.fb.com/MahmoudRFarra

Classification of data structure:

Data Structure

StructureLinear

Non-Linear

Memory Allocation

Static

Dynamic

Linear data structuremfarra.cst.ps www.fb.com/MahmoudRFarra

Linked List

Stack

Queue

Non-Linear data structuremfarra.cst.ps www.fb.com/MahmoudRFarra

Tree

Graph

Heap

Static memory allocationmfarra.cst.ps www.fb.com/MahmoudRFarra

Static memory allocation means the program must obtain its space before the execution and can not obtain more while or after execution.

Example: array data structure

Dynamic memory allocationmfarra.cst.ps www.fb.com/MahmoudRFarra

The dynamic memory allocation is the ability for a program to obtain more memory space at execution time to hold new nodes and to release space no longer needed.

Dynamic data structures as: Array lists, Vectors Linked Lists Stacks, Queues Trees, Heaps

Applications of data structuremfarra.cst.ps www.fb.com/MahmoudRFarra

Priority Queue: in banks, restaurants, … Hash Tables: in banks for combining two or more

accounts for matching Social Security Numbers. Family Tree Country Map Queue of tasks Order of operations in computer

Generic programmingmfarra.cst.ps www.fb.com/MahmoudRFarra

Generic programming refers to writing code that will work for many types of data.

Generics let you parameterize types. With this capability, you can define a class or a

method with generic types that the compiler can replace with concrete types.

Generic programmingmfarra.cst.ps www.fb.com/MahmoudRFarra

For example: Java defines a generic ArrayList class for

storing the elements of a generic type. From this generic class, you can create an

ArrayList object for holding strings and an ArrayList object for holding numbers.

Here, strings and numbers are concrete types that replace the generic type.

Collectionsmfarra.cst.ps www.fb.com/MahmoudRFarra

A Collection is a data type that is capable of holding a group of items.

The Collection interface defines the common operations for lists, vectors, stacks, queues, priority queues, and sets.

In Java, Collection classes can be implemented as a class, along with methods to add, remove, and examine items.

Think about a bag

Collection Classesmfarra.cst.ps www.fb.com/MahmoudRFarra

A bag can be put in its initial state, which is an empty bag.

Numbers can be added into the bag. You may check how many occurrences of a

certain number are in the bag. Numbers can be removed from the bag. You can check how many numbers are in the bag.

All the interfaces and classes defined in the Java Collections Framework are grouped in the java.util package.

Collection Classesmfarra.cst.ps www.fb.com/MahmoudRFarra

Examples

Collection classes in Java

Array List

Stack

Queue

List

Linked List

Heap

Sets store a group of nonduplicate elements. Lists store an ordered collection of elements. Stacks store objects that are processed in a last-in, first-out fashion. Queues store objects that are processed in a first-in, first-out fashion. PriorityQueues store objects that are processed in the order of their

priorities.

Collection Classesmfarra.cst.ps www.fb.com/MahmoudRFarra

Collection Testmfarra.cst.ps www.fb.com/MahmoudRFarra

import java.util.*;public class TestCollection {public static void main(String[] args) {ArrayList<String> collection1 = new ArrayList<>();collection1.add("New York");collection1.add("Atlanta");System.out.println("A list of cities in collection1:");System.out.println(collection1);System.out.println("\nIs Dallas in collection1? "+

collection1.contains("Dallas"));collection1.remove("Dallas");System.out.println("\n" + collection1.size() + " cities are in collection1

now");Collection<String> collection2 = new ArrayList<>();collection2.add("Seattle");collection2.add("Portland");System.out.println("\nA list of cities in collection2:");System.out.println(collection2);

Collection Testmfarra.cst.ps www.fb.com/MahmoudRFarra

The Collection interface contains the methods for manipulating the elements in a collection.

Big - Oh notation mfarra.cst.ps www.fb.com/MahmoudRFarra

We might be satisfied with evaluating the performance

or complexity of data structures by precisely counting

the number of statements executed or objects

referenced.

We adopt special notation to define upper bounds and lower bounds on functions.

In CS, usually the functions we are bounding are running times, memory requirements.

Big - Oh notation mfarra.cst.ps www.fb.com/MahmoudRFarra

using Java

2015

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