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Saturday, January 6, 2024

Key datastructure

 

Data structures are a specific way of organizing data in a specialized format on a computer so that the information can be organized, processed, stored, and retrieved quickly and effectively. They are a means of handling information, rendering the data for easy use.


List:

List are great for storing and manipulating ordered data.useful for task management, social media feeds, user preferences and shopping carts.

In task management application, list can use to store and organize task of each user. Tasks can be added, removed or reordered easily and user can mark them as complete or incomplete.

List are also useful in social media applications like Twitter where they can store and display user's feed in real time, ensuring the latest content is shown in the correct order


Array:

Provide fixed size, ordered collection of elements.Particularly well suited for situation where size of the collection is known and doesn't change frequently.

Array is commonly used in the mathematical operations, storing large data sets, or there is need for random access to elements.eg for a weather condition, array can be used to store temperature reading for a specific location over a defined period. This allows to calculate average and trends. It is also widely used in image processing, where each pixel data can be represented in a two dimensional array.

Stacks:

Stack follows last in first out principle (LIFO). They are perfect for supporting undo/redo operations in text editors or maintaining browser history in web browsers.

In text editor, stack can be used to store a each change made to text,making it simple to revert to previous state when user triggers an undo operation.


Queue:

Operates in First in first out basis (FIFO). They are good for managing printer jobs, sending user action in games, or handling messages in chat applications. In chat application, queue can be used to store the incoming messages in the order they are received. It ensures that are displayed to the recipient in the correct sequence. 


Heaps:

are used for task scheduling and memory management. They are especially helpful in implementing priority queues, where we need to access lowest or higher priority item efficiently.


Tree:

organize data hierarchically. They are useful for representing data with natural heirarchies and relationship. Can be used in various applications, like database indexing, AI decision making and file systems. In AI decision making, trees like decision trees are used in machine learning for classification tasks. Also used in database indexing, where they can help speed up search, delete or insert operations.For eg B tree and B+ trees are commonly used in relational databases to efficiently manage and index large amount of data.


Hash

Hash table allow for efficient data look up, insertion and deletion. They use hash function to map keys to their corresponding storage locations. It enables constant-time access to the stored values. Hash tables are widely used in various applications, such as search engine, caching system and programming language interpreters or compilers. In search engine hash table can used to store and quickly receive indexed data based on keywords.This provides fast and relevant search results. caching system may use hash table to store and manage cached data.It allows for rapid access to frequently requested resources and improves overall system performance.Another eg is maintaining the symbol table in programming language interperters or compilers. Also can be used to efficiently manage and lookup variables, functions and other symbols defined in the source code.


Suffix Trees

are specialized for searching strings in documents.This makes them perfect for text editors and search algorithms. In a search engine a suffix tree can be used to efficiently locate all occurances of the search term within a large corpus of text.


Graph

All about tracking relationship and finding paths. This makes them invaluable in social networks, recommendation engine and path finding algorithm. In social network graph can be used to represent the connection between users.It enables features like friends suggestions or analyzing network trends.


R-trees

good at finding nearest neighbours. They are good at mapping apps and geolocation services. In a mapping application r-tree can be used to store spatial data, such as point of interest, This enable efficient query to find the nearest location based on the user's current position. 


How all are related, let's understand with below eg.

CPU cache is a small, fast memory between the main memory(RAM) and the CPU.

It stores recently accessed data and instructions, so the cpu can access them quickly without fetching them from the slower main memory. Different data structure has various levels of cache friendliness based on how their elements are stored in memory. Contiguous memory storage like that in arrays allows for better cache locality and fewer cache misses, resulting in improved performance.

When an array element is accessed, the cache can pre-fetch and store nearby elements, anticipating that they can be accessed soon.

On the other hand data structure with non-contiguous memory storage, like linked list can experience more cache misses and reduced performance. In a linked list, elements are stored in a nodes scattered throughout the memory and each node contains a pointer to next node in a sequence. This makes it difficult for the CPU to predict and load the next node before it's needed.

Other data structure like trees, hash, graphs, also have varying degrees of cache friendliness based on their implementation and use cases. This disparity in access times can lead to performance issue in modern computing particularly in cases where cache misses occur frequently.  we need to choose data structure based on specific requirement

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Data structures are fundamental building blocks in computer science and are used to organize, store, and manipulate data efficiently. There are many different types of data structures, each with its own characteristics and use cases. Here are some key data structures and their common use cases:

1. **Arrays**:
   - An array is a collection of elements stored in contiguous memory locations, each identified by an index or key.
   - Use cases: Arrays are commonly used for storing and accessing a fixed-size collection of elements, such as lists of numbers, characters, or objects. They are efficient for random access but less efficient for insertion and deletion operations.

2. **Linked Lists**:
   - A linked list is a collection of nodes where each node contains a data element and a reference (pointer) to the next node in the sequence.
   - Use cases: Linked lists are useful for implementing dynamic data structures where elements can be inserted or removed efficiently, such as stacks, queues, and hash tables. They are also used in memory allocation and garbage collection algorithms.

3. **Stacks**:
   - A stack is a last-in, first-out (LIFO) data structure that supports two main operations: push (add element to the top) and pop (remove element from the top).
   - Use cases: Stacks are used for managing function calls, expression evaluation, backtracking algorithms, and implementing undo functionality in text editors.

4. **Queues**:
   - A queue is a first-in, first-out (FIFO) data structure that supports two main operations: enqueue (add element to the back) and dequeue (remove element from the front).
   - Use cases: Queues are used for managing tasks in scheduling algorithms, breadth-first search (BFS) traversal of graphs, and implementing message queues in concurrent programming.

5. **Trees**:
   - A tree is a hierarchical data structure composed of nodes, where each node has a value and zero or more child nodes.
   - Use cases: Trees are used for representing hierarchical relationships, organizing data in file systems and databases, implementing search and sorting algorithms (e.g., binary search tree), and building decision trees in machine learning.

6. **Graphs**:
   - A graph is a collection of nodes (vertices) and edges (connections) between them.
   - Use cases: Graphs are used for modeling relationships between objects (e.g., social networks, road networks), solving optimization problems (e.g., shortest path, minimum spanning tree), and representing complex data structures (e.g., dependency graphs).

7. **Hash Tables**:
   - A hash table is a data structure that maps keys to values using a hash function, allowing for fast retrieval and storage of data.
   - Use cases: Hash tables are used for implementing associative arrays, dictionaries, caches, and symbol tables in programming languages and databases.
These are just a few examples of common data structures and their use cases. Choosing the right data structure depends on factors such as the nature of the data, the operations that need to be performed on it, and the performance requirements of the application.


 




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