Coding Interview Resources
This channel contains the free resources and solution of coding problems which are usually asked in the interviews. Managed by: @love_data
Show more๐ Analytical overview of Telegram channel Coding Interview Resources
Channel Coding Interview Resources (@crackingthecodinginterview) in the English language segment is an active participant. Currently, the community unites 52 132 subscribers, ranking 2 574 in the Technologies & Applications category and 7 288 in the India region.
๐ Audience metrics and dynamics
Since its creation on ะฝะตะฒัะดะพะผะพ, the project has demonstrated rapid growth, gathering an audience of 52 132 subscribers.
According to the latest data from 04 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 183 over the last 30 days and by 8 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 1.84%. Within the first 24 hours after publication, content typically collects 0.82% reactions from the total number of subscribers.
- Post reach: On average, each post receives 960 views. Within the first day, a publication typically gains 425 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 2.
- Thematic interests: Content is focused on key topics such as array, stack, algorithm, programming, sort.
๐ Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
โThis channel contains the free resources and solution of coding problems which are usually asked in the interviews.
Managed by: @love_dataโ
Thanks to the high frequency of updates (latest data received on 05 June, 2026), the channel maintains relevance and a high level of publication reach. Analytics show that the audience actively interacts with content, making it an important point of influence in the Technologies & Applications category.
WHERE filters rows before grouping (used with SELECT, UPDATE).
โฆ HAVING filters groups after aggregation (used with GROUP BY), e.g., filtering aggregated results like sums or counts.
5. Write a SQL query to find the second highest salary in a table.
Using a subquery:
SELECT MAX(salary) FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
Or using DENSE_RANK():
SELECT salary FROM (
SELECT salary, DENSE_RANK() OVER (ORDER BY salary DESC) as rnk
FROM employees) t
WHERE rnk = 2;
6. What is a JOIN? Explain different types of JOINs.
A JOIN combines rows from two or more tables based on a related column:
โฆ INNER JOIN: returns matching rows from both tables.
โฆ LEFT JOIN (LEFT OUTER JOIN): all rows from the left table, matched rows from right.
โฆ RIGHT JOIN (RIGHT OUTER JOIN): all rows from right table, matched rows from left.
โฆ FULL JOIN (FULL OUTER JOIN): all rows when thereโs a match in either table.
โฆ CROSS JOIN: Cartesian product of both tables.
7. How do you optimize slow-performing SQL queries?
โฆ Use indexes appropriately to speed up lookups.
โฆ Avoid SELECT *; only select necessary columns.
โฆ Use joins carefully; filter early with WHERE clauses.
โฆ Analyze execution plans to identify bottlenecks.
โฆ Avoid unnecessary subqueries; use EXISTS or JOINs.
โฆ Limit result sets with pagination if dealing with large datasets.
8. What is a primary key? What is a foreign key?
โฆ Primary Key: A unique identifier for records in a table; it cannot be NULL.
โฆ Foreign Key: A field that creates a link between two tables by referring to the primary key in another table, enforcing referential integrity.
9. What are indexes? Explain clustered and non-clustered indexes.
โฆ Indexes speed up data retrieval by providing quick lookups.
โฆ Clustered Index: Sorts and stores the actual data rows in the table based on the key; a table can have only one clustered index.
โฆ Non-Clustered Index: Creates a separate structure that points to the data rows; tables can have multiple non-clustered indexes.
10. Write a SQL query to fetch the top 5 records from a table.
In SQL Server and PostgreSQL:
SELECT * FROM table_name
ORDER BY some_column DESC
LIMIT 5;
In SQL Server (older syntax):
SELECT TOP 5 * FROM table_name
ORDER BY some_column DESC;
React โฅ๏ธ for Part 2<article>, <section>, <nav>, <header>). Improves accessibility and SEO.
4. What is the DOM
Document Object Model โ a tree-like structure representing HTML elements. JavaScript can manipulate it to update content dynamically.
5. What is the difference between GET and POST methods
โข GET: Sends data via URL, used for fetching
โข POST: Sends data in body, used for submitting forms securely
6. What is the box model in CSS
Every HTML element is a box:
Content โ Padding โ Border โ Margin
7. What is the difference between relative, absolute, and fixed positioning in CSS
โข Relative: Moves element relative to its normal position
โข Absolute: Positions element relative to nearest positioned ancestor
โข Fixed: Stays in place even when scrolling
8. What is the difference between == and === in JavaScript
โข ==: Compares values with type coercion
โข ===: Strict comparison (value and type)
9. What is event bubbling in JavaScript
Events propagate from child to parent elements. Can be controlled using stopPropagation().
10. What is the difference between localStorage and sessionStorage
โข localStorage: Persistent across sessions
โข sessionStorage: Cleared when tab is closed
11. What is a RESTful API
An architectural style for designing networked applications using HTTP methods (GET, POST, PUT, DELETE) and stateless communication.
12. What is the difference between frontend and backend development
โข Frontend: Client-side (UI/UX, HTML/CSS/JS)
โข Backend: Server-side (databases, APIs, authentication)
13. What are common HTTP status codes
โข 200 OK
โข 404 Not Found
โข 500 Internal Server Error
โข 403 Forbidden
โข 301 Moved Permanently
14. What is a promise in JavaScript
An object representing the eventual completion or failure of an async operation.
States: pending, fulfilled, rejected
15. What is the difference between synchronous and asynchronous code
โข Synchronous: Executes line by line
โข Asynchronous: Executes independently, doesnโt block the main thread
16. What is a CSS preprocessor
Tools like SASS or LESS that add features to CSS (variables, nesting, mixins) and compile into standard CSS.
17. What is the role of frameworks like React, Angular, or Vue
They simplify building complex UIs with reusable components, state management, and routing.
18. What is the difference between SQL and NoSQL databases
โข SQL: Structured, relational (e.g., MySQL)
โข NoSQL: Flexible schema, document-based (e.g., MongoDB)
19. What is version control and why is Git important
Version control tracks changes in code. Git allows collaboration, branching, and rollback. Platforms: GitHub, GitLab, Bitbucket
20. How do you optimize website performance
โข Minify CSS/JS
โข Use lazy loading
โข Compress images
โข Use CDN
โข Reduce HTTP requests
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