Algorithm Basics

Algorithm

• A set of instructions to solve a specific problem or perform a particular task
• Characterized by:
  • Finiteness: The algorithm must always terminate after a finite number of steps
  • Definiteness: Each step must be precisely defined
  • Effectiveness: The algorithm can be carried out by a computer
  • Finiteness of description: The algorithm can be described in a finite amount of space
• Types:
  • Recursive algorithms: Divide the problem into smaller instances of the same problem
  • Dynamic programming algorithms: Break down the problem into smaller overlapping subproblems
  • Backtracking algorithms: Find a solution by recursively exploring possible solutions

Database

• A collection of organized data that can be easily accessed, managed, and updated
• Characteristics:
  • Persistence: Data is stored in a permanent storage device
  • Sharing: Multiple users can access the data concurrently
  • Data independence: Data is independent of the application program
• Types:
  • Relational databases: Organize data into tables with defined relationships
  • Object-oriented databases: Store data in the form of objects
  • NoSQL databases: Store data in a variety of formats (e.g., key-value, document, graph)

Operating System

• Software that manages computer hardware resources and provides common services to computer programs
• Functions:
  • Process management: Create, run, and manage processes
  • Memory management: Allocate and deallocate memory for programs
  • File system management: Create, delete, and manage files and directories
  • I/O management: Manage input/output operations between devices and programs
• Types:
  • Single-user, single-tasking OS: Support one user and one task at a time (e.g., MS-DOS)
  • Multi-user, multi-tasking OS: Support multiple users and multiple tasks concurrently (e.g., Windows, Linux)

Data Structure

• A way to organize and store data in a computer so that it can be efficiently accessed and modified
• Types:
  • Arrays: A collection of elements of the same data type stored in contiguous memory locations
  • Linked lists: A dynamic collection of elements, where each element points to the next element
  • Stacks: A last-in, first-out (LIFO) data structure with push and pop operations
  • Trees: A hierarchical data structure with nodes and edges
  • Graphs: A non-linear data structure with nodes and edges

Computer Network

• A collection of interconnected devices that communicate with each other to share resources
• Types:
  • LAN (Local Area Network): Connects devices in a limited geographical area
  • WAN (Wide Area Network): Connects devices over a larger geographical area
  • Wi-Fi network: A wireless network that connects devices using radio waves
• Network topologies:
  • Bus topology: A single cable connects all devices in a linear sequence
  • Star topology: Devices connect to a central hub or switch
  • Ring topology: Devices connect in a circular configuration
  • Mesh topology: Each device connects to every other device

Algorithm

• An algorithm is a set of instructions to solve a specific problem or perform a particular task
• Characterized by finiteness, definiteness, effectiveness, and finiteness of description
• Recursive algorithms divide the problem into smaller instances of the same problem
• Dynamic programming algorithms break down the problem into smaller overlapping subproblems
• Backtracking algorithms find a solution by recursively exploring possible solutions

Database

• A database is a collection of organized data that can be easily accessed, managed, and updated
• Data is stored in a permanent storage device (persistence)
• Multiple users can access the data concurrently (sharing)
• Data is independent of the application program (data independence)
• Relational databases organize data into tables with defined relationships
• Object-oriented databases store data in the form of objects
• NoSQL databases store data in a variety of formats (e.g., key-value, document, graph)

Operating System

• An operating system is software that manages computer hardware resources and provides common services to computer programs
• Functions include process management, memory management, file system management, and I/O management
• Process management involves creating, running, and managing processes
• Memory management involves allocating and deallocating memory for programs
• File system management involves creating, deleting, and managing files and directories
• I/O management involves managing input/output operations between devices and programs
• Single-user, single-tasking OS support one user and one task at a time
• Multi-user, multi-tasking OS support multiple users and multiple tasks concurrently

Data Structure

• A data structure is a way to organize and store data in a computer so that it can be efficiently accessed and modified
• Arrays are a collection of elements of the same data type stored in contiguous memory locations
• Linked lists are a dynamic collection of elements, where each element points to the next element
• Stacks are a last-in, first-out (LIFO) data structure with push and pop operations
• Trees are a hierarchical data structure with nodes and edges
• Graphs are a non-linear data structure with nodes and edges

Computer Network

• A computer network is a collection of interconnected devices that communicate with each other to share resources
• Types of networks include LAN, WAN, and Wi-Fi
• LAN connects devices in a limited geographical area
• WAN connects devices over a larger geographical area
• Network topologies include bus, star, ring, and mesh
• Bus topology involves a single cable connecting all devices in a linear sequence
• Star topology involves devices connecting to a central hub or switch
• Ring topology involves devices connecting in a circular configuration
• Mesh topology involves each device connecting to every other device