Data structures and algorithms are the single most important topics in software development, in my opinion. Consider it the essential tool at the disposal of every computer programmer. We utilize data structures to store and organize data while programming, and algorithms to manipulate the data in those structures. This article provides a thorough examination of all common data structures and algorithms in Java, allowing users to become well-equipped.

Listed below are the topics discussed in this article:

• Data Structures in Java

1. Linear Data Structures

2. Hierarchical Data Structures

• Algorithms in Java

1. Sorting Algorithms

2. Searching Algorithms

Data Structures in Java

A data structure is a method of storing and organizing data in a computer to make it more usable. It allows for the efficient management of massive amounts of data. And efficient data structures are essential for creating efficient algorithms.

In this 'Data Structures and Algorithms in Java' article, we'll go over fundamental data structures like:

• Linear Data Structures

  1. Array

  2. Linked List

  3. Stacks

  4. Queues

• Hierarchical Data Structures

1. Binary Trees

2. Heaps

3. Hash Tables

Java Linear Data Structures

Linear data structures in Java have elements that are sequential and organized in such a way that there is only one first element and one next element, only one last element and one previous element, and all other items have a next and a prior element.

Arrays

An array is a linear data structure that represents a collection of comparable components that may be retrieved by index. Before saving data, the array's size must be specified. An array's properties are as follows:

• Each element in an array is of the same data type and has the same size

• Elements of the array are stored at contiguous memory locations with the first element starting at the smallest memory location

• Elements of the array can be randomly accessed

• The array data structure is not completely dynamic

For example, we would want a video game to keep track of the top ten scores. Instead of 10 individual variables, we could use a single name for the entire group and index numbers to refer to the high scores in that group.

Linked Lists

A linked list is a linear data structure composed of many nodes, each of which holds its own data as well as a pointer to the location of the next element. The last link in a linked list links to null, indicating that the chain has come to an end. A node is an element in a linked list. The first node is referred to as the head. The last node is known as the tail.

Types of Linked List

Singly Linked List (Uni-Directional)

Doubly Linked List (Bi-Directional)

Circular Linked List

Here's an easy example:

Consider a linked list to be a chain of paperclips connected together. Another paperclip can be easily added to the top or bottom. It's even easier to put one in the middle. Simply disconnect the chain in the middle, insert the new paperclip, and reconnect the other half. A linked list is comparable.

Stacks

An abstract data structure called a stack is a collection of things that are inserted and removed using the last-in-first-out (LIFO) principle. Objects can be added to a stack at any moment, but only the most recently added (that is, "last") object can be removed. The following are stack properties:

• It is an orderd list in which insertion and deletion can be performed only at one end that is called the top

• Recursive data structure with a pointer to its top element

• Follows the last-in-first-out (LIFO) principle

• Supports two most fundamental methods

1. push(e): Insert element e, to the top of the stack

2. pop(): Remove and return the top element on the stack

Practical examples of the stack include when reversing a word, to check the correctness of parentheses sequence, implementing back functionality in browsers and many more.

Queues

Queues are a type of abstract data structure as well. The queue, unlike a stack, is a collection of objects that are inserted and withdrawn in accordance with the first-in-first-out (FIFO) principle. That is, elements can be inserted at any moment, but only the element with the longest duration in the queue can be removed at any time. A queue's properties are as follows:

• Often referred to as the first-in-first-out list

• Supports two most fundamental methods

1. enqueue(e): Insert element e, at the rear of the queue

2. dequeue(): Remove and return the element from the front of the queue

Queues are used in the asynchronous transfer of data between two processes, CPU scheduling, Disk Scheduling and other situations where resources are shared among multiple users and served on first come first server basis.