Coding Interview Resources – Telegram
Coding Interview Resources
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This channel contains the free resources and solution of coding problems which are usually asked in the interviews.

Managed by: @love_data
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Few common problems with lot of resumes:

1. 𝐈𝐫𝐫𝐞𝐥𝐞𝐯𝐚𝐧𝐭 𝐢𝐧𝐟𝐨𝐫𝐦𝐚𝐭𝐢𝐨𝐧.
I understand that there are a lot of achievements that we are personally proud of (things like represented school/clg in XYZ competition or school head/class head etc), but not all of them are relevant to technical roles. As a fresher, try to focus more on technical achievements rather than managerial ones.

2. 𝐋𝐚𝐜𝐤 𝐨𝐟 𝐪𝐮𝐚𝐥𝐢𝐭𝐲 𝐩𝐫𝐨𝐣𝐞𝐜𝐭𝐬.
Many resumes have the same common projects, such as:
Creating just the front-end using HTML and CSS and redirecting all the work to an open-source API (e.g., weather prediction and recipe suggestion apps).

Most common projects are: -
Tic-tac-toe game.
Sorting algorithms visualizers.
To-do application.
Movie listing.

The codes for these projects are often copied and pasted from GitHub repositories.

Projects are like a bounty. If you are prepared well and have quality projects in your resume, you can set the tempo of the interview. It is one of the few questions that you will almost certainly be asked in the interview.

I don't understand why we can spend 2 years preparing for data structures and algorithms (DSA) and competitive programming (CP), but not even 2 weeks to create quality projects.
Even if your resume passes the applicant tracking system (ATS) and recruiter's screening, weak projects can still lead to your rejection in interviews. And this is completely in your hands.

I feel that this topic needs a lot more discussion about the type and quality of projects that one needs. Let me know if you want a dedicated post on this.

3. 𝐋𝐚𝐜𝐤 𝐨𝐟 𝐪𝐮𝐚𝐧𝐭𝐢𝐭𝐚𝐭𝐢𝐯𝐞 𝐝𝐚𝐭𝐚.
For technical roles, adding quantitative data has a big impact.
For example, instead of saying "I wrote unit tests for service X and reduced the latency of service Y by caching," you can say "I wrote unit tests and increased the code coverage from 80% to 95% of service X and reduced latency from 100 milliseconds to 50 milliseconds of service Y."
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⌨️ JavaScript Array methods
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REST API Common Misconceptions
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📚👀🚀Preparing for a Data science/ Data Analytics interview can be challenging, but with the right strategy, you can enhance your chances of success. Here are some key tips to assist you in getting ready:

Review Fundamental Concepts: Ensure you have a strong grasp of statistics, probability, linear algebra, data structures, algorithms, and programming languages like Python, R, and SQL.

Refresh Machine Learning Knowledge: Familiarize yourself with various machine learning algorithms, including supervised, unsupervised, and reinforcement learning.

Practice Coding: Sharpen your coding skills by solving data science-related problems on platforms like HackerRank, LeetCode, and Kaggle.

Build a Project Portfolio: Showcase your proficiency by creating a portfolio highlighting projects covering data cleaning, wrangling, exploratory data analysis, and machine learning.

Hone Communication Skills: Practice articulating complex technical ideas in simple terms, as effective communication is vital for data scientists when interacting with non-technical stakeholders.

Research the Company: Gain insights into the company's operations, industry, and how they leverage data to solve challenges.

🧠👍By adhering to these guidelines, you'll be well-prepared for your upcoming data science interview. Best of luck!

Hope this helps 👍❤️:⁠-⁠)

👍👀Be the first one to know the latest Job openings
https://whatsapp.com/channel/0029VaI5CV93AzNUiZ5Tt226
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1. What is the AdaBoost Algorithm?
AdaBoost also called Adaptive Boosting is a technique in Machine Learning used as an Ensemble Method. The most common algorithm used with AdaBoost is decision trees with one level that means with Decision trees with only 1 split. These trees are also called Decision Stumps. What this algorithm does is that it builds a model and gives equal weights to all the data points. It then assigns higher weights to points that are wrongly classified. Now all the points which have higher weights are given more importance in the next model. It will keep training models until and unless a lower error is received.

2. What is the Sliding Window method for Time Series Forecasting?

Time series can be phrased as supervised learning. Given a sequence of numbers for a time series dataset, we can restructure the data to look like a supervised learning problem.
In the sliding window method, the previous time steps can be used as input variables, and the next time steps can be used as the output variable.
In statistics and time series analysis, this is called a lag or lag method. The number of previous time steps is called the window width or size of the lag. This sliding window is the basis for how we can turn any time series dataset into a supervised learning problem.


3. What do you understand by sub-queries in SQL?

A subquery is a query inside another query where a query is defined to retrieve data or information back from the database. In a subquery, the outer query is called as the main query whereas the inner query is called subquery. Subqueries are always executed first and the result of the subquery is passed on to the main query. It can be nested inside a SELECT, UPDATE or any other query. A subquery can also use any comparison operators such as >,< or =.


4. Explain the Difference Between Tableau Worksheet, Dashboard, Story, and Workbook?

Tableau uses a workbook and sheet file structure, much like Microsoft Excel.
A workbook contains sheets, which can be a worksheet, dashboard, or a story.
A worksheet contains a single view along with shelves, legends, and the Data pane.
A dashboard is a collection of views from multiple worksheets.
A story contains a sequence of worksheets or dashboards that work together to convey information.


5. How is a Random Forest related to Decision Trees?

Random forest is an ensemble learning method that works by constructing a multitude of decision trees. A random forest can be constructed for both classification and regression tasks.
Random forest outperforms decision trees, and it also does not have the habit of overfitting the data as decision trees do.
A decision tree trained on a specific dataset will become very deep and cause overfitting. To create a random forest, decision trees can be trained on different subsets of the training dataset, and then the different decision trees can be averaged with the goal of decreasing the variance.


6. What are some disadvantages of using Naive Bayes Algorithm?

Some disadvantages of using Naive Bayes Algorithm are:
It relies on a very big assumption that the independent variables are not related to each other.
It is generally not suitable for datasets with large numbers of numerical attributes.
It has been observed that if a rare case is not in the training dataset but is in the testing dataset, then it will most definitely be wrong.
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🧿 Boost React Performance

Performance bottlenecks in React often come from unnecessary re-renders and poor state management. Here’s a straightforward guide to optimizing your React apps.
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Roadmap to become a Programmer:

📂 Learn Programming Fundamentals (Logic, Syntax, Flow)
📂 Choose a Language (Python / Java / C++)
📂 Learn Data Structures & Algorithms
📂 Learn Problem Solving (LeetCode / HackerRank)
📂 Learn OOPs & Design Patterns
📂 Learn Version Control (Git & GitHub)
📂 Learn Debugging & Testing
📂 Work on Real-World Projects
📂 Contribute to Open Source
Apply for Job / Internship

React ❤️ for More 💡
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If you want to Excel at using one of the most powerful programming languages in the world, learn these essential Python features:

List Comprehensions – [x for x in range(10) if x % 2 == 0]
Lambda Functions – lambda x: x * 2
Map, Filter, Reduce – Functional programming magic
F-strings – f"Hello, {name}!" (Best way to format strings)
Enumerate & Zip – Iterate smarter
Generators & Yield – Efficient memory usage
Exception Handling – try-except-finally for error-proof code
Decorators – @staticmethod, @classmethod, @property
Pandas & NumPy – Data manipulation & numerical computing
Async Programming – Speed up tasks with asyncio

Free Python Resources: 👇
https://whatsapp.com/channel/0029VaiM08SDuMRaGKd9Wv0L

Like it if you need a complete tutorial on all these topics! 👍❤️
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YouTube channels for web development languages:

𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝗟𝗮𝗻𝗴𝘂𝗮𝗴𝗲𝘀 & 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸𝘀
HTML/CSS 🎨 – Kevin Powell
JavaScript 🌐 – The Net Ninja
TypeScript 📘 – Academind
React ⚛️ – Traversy Media
Angular 🔺 – Academind
Vue. js 🟩 – Vue Mastery

𝗕𝗮𝗰𝗸𝗲𝗻𝗱 𝗟𝗮𝗻𝗴𝘂𝗮𝗴𝗲𝘀 & 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸𝘀
Node. js 🚀 – Traversy Media
PHP 🐘 – PHP Academy
Ruby on Rails 💎 – Drifting Ruby
Django (Python) 🐍 – Corey Schafer
Flask (Python) 🔥 – Pretty Printed
ASP. NET (C#) 🎯 – IAmTimCorey

𝗗𝗮𝘁𝗮𝗯𝗮𝘀𝗲𝘀 & 𝗗𝗲𝘃𝗢𝗽𝘀
SQL 🗄️ – DataSimplifier
MongoDB 🍃 – MongoDB Official
Docker 🐳 – TechWorld with Nana

React ❤️ for more
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💻 Popular Coding Languages & Their Uses 🚀

There are many programming languages, each serving different purposes. Here are some key ones you should know:

🔹 1. Python – Beginner-friendly, versatile, and widely used in data science, AI, web development, and automation.

🔹 2. JavaScript – Essential for frontend and backend web development, powering interactive websites and applications.

🔹 3. Java – Used for enterprise applications, Android development, and large-scale systems due to its stability.

🔹 4. C++ – High-performance language ideal for game development, operating systems, and embedded systems.

🔹 5. C# – Commonly used in game development (Unity), Windows applications, and enterprise software.

🔹 6. Swift – The go-to language for iOS and macOS development, known for its efficiency.

🔹 7. Go (Golang) – Designed for high-performance applications, cloud computing, and network programming.

🔹 8. Rust – Focuses on memory safety and performance, making it great for system-level programming.

🔹 9. SQL – Essential for database management, allowing efficient data retrieval and manipulation.

🔹 10. Kotlin – Popular for Android app development, offering modern features compared to Java.

🔥 React ❤️ for more 😊🚀
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𝐒𝐐𝐋 𝐂𝐚𝐬𝐞 𝐒𝐭𝐮𝐝𝐢𝐞𝐬 𝐟𝐨𝐫 𝐈𝐧𝐭𝐞𝐫𝐯𝐢𝐞𝐰:

Join for more: https://news.1rj.ru/str/sqlanalyst

1. Danny’s Diner:
Restaurant analytics to understand the customer orders pattern.
Link: https://8weeksqlchallenge.com/case-study-1/

2. Pizza Runner
Pizza shop analytics to optimize the efficiency of the operation
Link: https://8weeksqlchallenge.com/case-study-2/

3. Foodie Fie
Subnoscription-based food content platform
Link: https://lnkd.in/gzB39qAT

4. Data Bank: That’s money
Analytics based on customer activities with the digital bank
Link: https://lnkd.in/gH8pKPyv

5. Data Mart: Fresh is Best
Analytics on Online supermarket
Link: https://lnkd.in/gC5bkcDf

6. Clique Bait: Attention capturing
Analytics on the seafood industry
Link: https://lnkd.in/ggP4JiYG

7. Balanced Tree: Clothing Company
Analytics on the sales performance of clothing store
Link: https://8weeksqlchallenge.com/case-study-7

8. Fresh segments: Extract maximum value
Analytics on online advertising
Link: https://8weeksqlchallenge.com/case-study-8
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Top 10 Coding Interview Questions (2025) 💼👨‍💻

1️⃣ Subarray with given sum 
Find continuous subarray that sums to a target value.

2️⃣ Count triplets with given sum 
Find triplets in array whose sum equals a target.

3️⃣ Kadane’s Algorithm 
Find maximum sum subarray in O(n).

4️⃣ Missing number in array 
Find the one number missing from 1 to N.

5️⃣ Sort an array of 0s, 1s and 2s 
Dutch National Flag problem — sort in a single scan.

6️⃣ Depth First Traversal (Graph) 
Traverse graph nodes using stack or recursion.

7️⃣ Topological Sort 
Order nodes in a Directed Acyclic Graph (DAG).

8️⃣ Activity Selection (Greedy) 
Select max non-overlapping activities.

9️⃣ Longest Increasing Subsequence (DP) 
Find length of longest increasing subsequence in array.

🔟 N-Queen Problem (Backtracking) 
Place N queens on an N×N board so none attack each other.

💬 Tap ❤️ for more
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Master Power BI with this Cheat Sheet🔥

If you're preparing for a Power BI interview, this cheat sheet covers the key concepts and DAX commands you'll need. Bookmark it for last-minute revision!

📝 𝗣𝗼𝘄𝗲𝗿 𝗕𝗜 𝗕𝗮𝘀𝗶𝗰𝘀:

DAX Functions:

- SUMX: Sum of values based on a condition.
- FILTER: Filter data based on a given condition.
- RELATED: Retrieve a related column from another table.
- CALCULATE: Perform dynamic calculations.
- EARLIER: Access a column from a higher context.
- CROSSJOIN: Create a Cartesian product of two tables.
- UNION: Combine the results from multiple tables.
- RANKX: Rank data within a column.
- DISTINCT: Filter unique rows.

Data Modeling:

- Relationships: Create, manage, and modify relationships.
- Hierarchies: Build time-based hierarchies (e.g., Date, Month, Year).
- Calculated Columns: Create calculated columns to extend data.
- Measures: Write powerful measures to analyze data effectively.

Data Visualization:

- Charts: Bar charts, line charts, pie charts, and more.
- Table & Matrix: Display tabular data and matrix visuals.
- Slicers: Create interactive filters.
- Tooltips: Enhance visual interactivity with tooltips.
- Map: Display geographical data effectively.

𝗘𝘀𝘀𝗲𝗻𝘁𝗶𝗮𝗹 𝗣𝗼𝘄𝗲𝗿 𝗕𝗜 𝗧𝗶𝗽𝘀:

Use DAX for efficient data analysis.

Optimize data models for performance.

Utilize drill-through and drill-down for deeper insights.

Leverage bookmarks for enhanced navigation.

Annotate your reports with comments for clarity.

Like this post if you need more content like this 👍❤️
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Some important questions to crack data science interview

Q. Describe how Gradient Boosting works.

A. Gradient boosting is a type of machine learning boosting. It relies on the intuition that the best possible next model, when combined with previous models, minimizes the overall prediction error. If a small change in the prediction for a case causes no change in error, then next target outcome of the case is zero. Gradient boosting produces a prediction model in the form of an ensemble of weak prediction models, typically decision trees.


Q. Describe the decision tree model.

A. Decision Trees are a type of Supervised Machine Learning where the data is continuously split according to a certain parameter. The leaves are the decisions or the final outcomes. A decision tree is a machine learning algorithm that partitions the data into subsets.


Q. What is a neural network?

A. Neural networks are a set of algorithms, modeled loosely after the human brain, that are designed to recognize patterns. They interpret sensory data through a kind of machine perception, labeling or clustering raw input. They, also known as Artificial Neural Networks, are the subset of Deep Learning.


Q. Explain the Bias-Variance Tradeoff

A. The bias–variance tradeoff is the property of a model that the variance of the parameter estimated across samples can be reduced by increasing the bias in the estimated parameters.


Q. What’s the difference between L1 and L2 regularization?

A. The main intuitive difference between the L1 and L2 regularization is that L1 regularization tries to estimate the median of the data while the L2 regularization tries to estimate the mean of the data to avoid overfitting. That value will also be the median of the data distribution mathematically.

ENJOY LEARNING 👍👍
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