An introduction to Data Structures

Data Structures: The Ultimate Guide

Welcome to our in-depth guide on Data Structures — the backbone of efficient software and system design. Whether you're a beginner learning to code or an experienced developer looking to brush up, this guide will help you understand, compare, and choose the right data structures for your projects.

What is a Data Structure?

A data structure is a specialized format for organizing, processing, retrieving, and storing data. It dictates how data is logically and physically arranged in memory so operations like search, insert, delete, and update can be performed efficiently.

Linear Data Structures

1. Array

• Definition: A collection of elements stored at contiguous memory locations.

• Operations: Access (O(1)), Insert/Delete (O(n))

• Types: 1D, 2D, Multidimensional

• Advantages:

  • Fast access with index

• Limitations:

  • Fixed size

  • Costly insert/delete

int arr[5] = {1, 2, 3, 4, 5};

2. Linked List

• Definition: A sequence of nodes where each node contains data and a pointer to the next.

• Types: Singly, Doubly, Circular

• Operations:

  • Insert/Delete: O(1) (beginning)

  • Search: O(n)

• Advantages:

  • Dynamic size

  • Efficient insert/delete

• Limitations:

  • No random access

  • Extra memory for pointers

struct Node {
  int data;
  Node* next;
};

3. Stack (LIFO)

• Definition: Last-In-First-Out structure

• Operations:

  • Push (Insert)

  • Pop (Remove)

  • Peek (Top element)

• Time Complexity: O(1) for all operations

• Applications:

  • Undo mechanisms

  • Syntax parsing

  • Recursion

4. Queue (FIFO)

• Definition: First-In-First-Out structure

• Types:

  • Simple Queue

  • Circular Queue

  • Deque (Double-ended)

  • Priority Queue

• Operations: Enqueue, Dequeue, Peek

• Time Complexity: O(1) with efficient implementation

• Applications:

  • Task scheduling

  • Print queues

  • BFS traversal