https://roadmap.sh/backend everything at one place. Enjoy

Xpath Guide.pdf

Common Programming Interview Questions

    How do you reverse a string?
    How do you determine if a string is a palindrome?
    How do you calculate the number of numerical digits in a string?
    How do you find the count for the occurrence of a particular character in a string?
    How do you find the non-matching characters in a string?
    How do you find out if the two given strings are anagrams?
    How do you calculate the number of vowels and consonants in a string?
    How do you total all of the matching integer elements in an array?
    How do you reverse an array?
    How do you find the maximum element in an array?
    How do you sort an array of integers in ascending order?
    How do you print a Fibonacci sequence using recursion?
    How do you calculate the sum of two integers?
    How do you find the average of numbers in a list?
    How do you check if an integer is even or odd?
    How do you find the middle element of a linked list?
    How do you remove a loop in a linked list?
    How do you merge two sorted linked lists?
    How do you implement binary search to find an element in a sorted array?
    How do you print a binary tree in vertical order?

Conceptual Coding Interview Questions

    What is a data structure?
    What is an array?
    What is a linked list?
    What is the difference between an array and a linked list?
    What is LIFO?
    What is FIFO?
    What is a stack?
    What are binary trees?
    What are binary search trees?
    What is object-oriented programming?
    What is the purpose of a loop in programming?
    What is a conditional statement?
    What is debugging?
    What is recursion?
    What are the differences between linear and non-linear data structures?


General Coding Interview Questions

    What programming languages do you have experience working with?
    Describe a time you faced a challenge in a project you were working on and how you overcame it.
    Walk me through a project you’re currently or have recently worked on.
    Give an example of a project you worked on where you had to learn a new programming language or technology. How did you go about learning it?
    How do you ensure your code is readable by other developers?
    What are your interests outside of programming?
    How do you keep your skills sharp and up to date?
    How do you collaborate on projects with non-technical team members?
    Tell me about a time when you had to explain a complex technical concept to a non-technical team member.
    How do you get started on a new coding project?

All the best 👍👍

🚨Here is a comprehensive list of #interview questions that are commonly asked in job interviews for Data Scientist, Data Analyst, and Data Engineer positions:


➡️ Data Scientist Interview Questions


Technical Questions

1) What are your preferred programming languages for data science, and why?

2) Can you write a Python script to perform data cleaning on a given dataset?

3) Explain the Central Limit Theorem.

4) How do you handle missing data in a dataset?

5) Describe the difference between supervised and unsupervised learning.

6) How do you select the right algorithm for your model?


Questions Related To Problem-Solving and Projects

7) Walk me through a data science project you have worked on.

8) How did you handle data preprocessing in your project?

9) How do you evaluate the performance of a machine learning model?

10) What techniques do you use to prevent overfitting?


➡️Data Analyst Interview Questions


Technical Questions

1) Write a SQL query to find the second highest salary from the employee table.

2) How would you optimize a slow-running query?

3) How do you use pivot tables in Excel?

4) Explain the VLOOKUP function.

5) How do you handle outliers in your data?

6) Describe the steps you take to clean a dataset.


Analytical Questions

7) How do you interpret data to make business decisions?

8) Give an example of a time when your analysis directly influenced a business decision.

9) What are your preferred tools for data analysis and why?

10) How do you ensure the accuracy of your analysis?


➡️Data Engineer Interview Questions


Technical Questions

1) What is your experience with SQL and NoSQL databases?

2) How do you design a scalable database architecture?

3) Explain the ETL process you follow in your projects.

4) How do you handle data transformation and loading efficiently?

5) What is your experience with Hadoop/Spark?

6) How do you manage and process large datasets?


Questions Related To Problem-Solving and Optimization

7) Describe a data pipeline you have built.

8) What challenges did you face, and how did you overcome them?

9) How do you ensure your data processes run efficiently?

10) Describe a time when you had to optimize a slow data pipeline.

Study these 45 problems well and you have prepared for 99% of your System Design Interview:

𝐄𝐚𝐬𝐲
1. Design URL Shortener like TinyURL
2. Design Text Storage Service like Pastebin
3. Design Content Delivery Network (CDN)
4. Design Parking Garage
5. Design Vending Machine
6. Design Distributed Key-Value Store
7. Design Distributed Cache
8. Design Distributed Job Scheduler
9. Design Authentication System
10. Design Unified Payments Interface (UPI)

𝐌𝐞𝐝𝐢𝐮𝐦
11. Design Instagram
12. Design Tinder
13. Design WhatsApp
14. Design Facebook
15. Design Twitter
16. Design Reddit
17. Design Netflix
18. Design Youtube
19. Design Google Search
20. Design E-commerce Store like Amazon
21. Design Spotify
22. Design TikTok
23. Design Shopify
24. Design Airbnb
25. Design Autocomplete for Search Engines
26. Design Rate Limiter
27. Design Distributed Message Queue like Kafka
28. Design Flight Booking System
29. Design Online Code Editor
30. Design Stock Exchange System
31. Design an Analytics Platform (Metrics & Logging)
32. Design Notification Service
33. Design Payment System

𝐇𝐚𝐫𝐝
34. Design Location Based Service like Yelp
35. Design Uber
36. Design Food Delivery App like Doordash
37. Design Google Docs
38. Design Google Maps
39. Design Zoom
40. Design File Sharing System like Dropbox
41. Design Ticket Booking System like BookMyShow
42. Design Distributed Web Crawler
43. Design Code Deployment System
44. Design Distributed Cloud Storage like S3
45. Design Distributed Locking Service

Data Analyst Interview QnA

1. Find avg of salaries department wise from table.

Answer-

SELECT department_id, AVG(salary) AS avg_salary
FROM employees
GROUP BY department_id;

2. What does Filter context in DAX mean?

Answer - Filter context in DAX refers to the subset of data that is actively being used in the calculation of a measure or in the evaluation of an expression. This context is determined by filters on the dashboard items like slicers, visuals, and filters pane which restrict the data being processed.

3. Explain how to implement Row-Level Security (RLS) in Power BI.

Answer - Row-Level Security (RLS) in Power BI can be implemented by:

- Creating roles within the Power BI service.
- Defining DAX expressions that specify the data each role can access.
- Assigning users to these roles either in Power BI or dynamically through AD group membership.

4. Create a dictionary, add elements to it, modify an element, and then print the dictionary in alphabetical order of keys.

Answer -

d = {'apple': 2, 'banana': 5}
d['orange'] = 3  # Add element
d['apple'] = 4   # Modify element
sorted_d = dict(sorted(d.items()))  # Sort dictionary
print(sorted_d)

5. Find and print duplicate values in a list of assorted numbers, along with the number of times each value is repeated.

Answer -

from collections import Counter

numbers = [1, 2, 2, 3, 4, 5, 1, 6, 7, 3, 8, 1]
count = Counter(numbers)
duplicates = {k: v for k, v in count.items() if v > 1}
print(duplicates)

Many data scientists don't know how to push ML models to production. Here's the recipe 👇

𝗞𝗲𝘆 𝗜𝗻𝗴𝗿𝗲𝗱𝗶𝗲𝗻𝘁𝘀

🔹 𝗧𝗿𝗮𝗶𝗻 / 𝗧𝗲𝘀𝘁 𝗗𝗮𝘁𝗮𝘀𝗲𝘁 - Ensure Test is representative of Online data
🔹 𝗙𝗲𝗮𝘁𝘂𝗿𝗲 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 𝗣𝗶𝗽𝗲𝗹𝗶𝗻𝗲 - Generate features in real-time
🔹 𝗠𝗼𝗱𝗲𝗹 𝗢𝗯𝗷𝗲𝗰𝘁 - Trained SkLearn or Tensorflow Model
🔹 𝗣𝗿𝗼𝗷𝗲𝗰𝘁 𝗖𝗼𝗱𝗲 𝗥𝗲𝗽𝗼 - Save model project code to Github
🔹 𝗔𝗣𝗜 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸 - Use FastAPI or Flask to build a model API
🔹 𝗗𝗼𝗰𝗸𝗲𝗿 - Containerize the ML model API
🔹 𝗥𝗲𝗺𝗼𝘁𝗲 𝗦𝗲𝗿𝘃𝗲𝗿 - Choose a cloud service; e.g. AWS sagemaker
🔹 𝗨𝗻𝗶𝘁 𝗧𝗲𝘀𝘁𝘀 - Test inputs & outputs of functions and APIs
🔹 𝗠𝗼𝗱𝗲𝗹 𝗠𝗼𝗻𝗶𝘁𝗼𝗿𝗶𝗻𝗴 - Evidently AI, a simple, open-source for ML monitoring

𝗣𝗿𝗼𝗰𝗲𝗱𝘂𝗿𝗲

𝗦𝘁𝗲𝗽 𝟭 - 𝗗𝗮𝘁𝗮 𝗣𝗿𝗲𝗽𝗮𝗿𝗮𝘁𝗶𝗼𝗻 & 𝗙𝗲𝗮𝘁𝘂𝗿𝗲 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴

Don't push a model with 90% accuracy on train set. Do it based on the test set - if and only if, the test set is representative of the online data. Use SkLearn pipeline to chain a series of model preprocessing functions like null handling.

𝗦𝘁𝗲𝗽 𝟮 - 𝗠𝗼𝗱𝗲𝗹 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁

Train your model with frameworks like Sklearn or Tensorflow. Push the model code including preprocessing, training and validation scripts to Github for reproducibility.

𝗦𝘁𝗲𝗽 𝟯 - 𝗔𝗣𝗜 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 & 𝗖𝗼𝗻𝘁𝗮𝗶𝗻𝗲𝗿𝗶𝘇𝗮𝘁𝗶𝗼𝗻

Your model needs a "/predict" endpoint, which receives a JSON object in the request input and generates a JSON object with the model score in the response output. You can use frameworks like FastAPI or Flask. Containzerize this API so that it's agnostic to server environment

𝗦𝘁𝗲𝗽 𝟰 - 𝗧𝗲𝘀𝘁𝗶𝗻𝗴 & 𝗗𝗲𝗽𝗹𝗼𝘆𝗺𝗲𝗻𝘁

Write tests to validate inputs & outputs of API functions to prevent errors. Push the code to remote services like AWS Sagemaker.

𝗦𝘁𝗲𝗽 𝟱 - 𝗠𝗼𝗻𝗶𝘁𝗼𝗿𝗶𝗻𝗴

Set up monitoring tools like Evidently AI, or use a built-in one within AWS Sagemaker. I use such tools to track performance metrics and data drifts on online data.



Like if you need similar content 😄👍

Here is how you can explain your project in an interview:

When you’re in an interview, it’s super important to know how to talk about your projects in a way that impresses the interviewer. Here are some key points to help you do just that:

➤ 𝗣𝗿𝗼𝗷𝗲𝗰𝘁 𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄:

Start with a quick summary of the project you worked on. What was it all about? What were the main goals? Keep it short and sweet, something you can explain in about 30 seconds.


➤ 𝗣𝗿𝗼𝗯𝗹𝗲𝗺 𝗦𝘁𝗮𝘁𝗲𝗺𝗲𝗻𝘁:

What problem were you trying to solve with this project? Explain why this problem was important and needed addressing.


➤ 𝗣𝗿𝗼𝗽𝗼𝘀𝗲𝗱 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻:

Describe the solution you came up with. How does it work, and why is it a good fix for the problem?


➤ 𝗬𝗼𝘂𝗿 𝗥𝗼𝗹𝗲:

Talk about what you specifically did. What were your main tasks? Did you face any challenges, and how did you overcome them? Make sure it’s clear whether you were leading the project, a key player, or supporting the team.


➤ 𝗧𝗲𝗰𝗵𝗻𝗼𝗹𝗼𝗴𝗶𝗲𝘀 𝗮𝗻𝗱 𝗧𝗼𝗼𝗹𝘀:

Mention the tech and tools you used. This shows your technical know-how and your ability to choose the right tools for the job.


➤ 𝗜𝗺𝗽𝗮𝗰𝘁 𝗮𝗻𝗱 𝗔𝗰𝗵𝗶𝗲𝘃𝗲𝗺𝗲𝗻𝘁𝘀:

Share the results of your project. Did it make things better? How? Mention any improvements, efficiencies, or positive feedback you got. This helps show the project was a success and highlights your contribution.


➤ 𝗧𝗲𝗮𝗺 𝗖𝗼𝗹𝗹𝗮𝗯𝗼𝗿𝗮𝘁𝗶𝗼𝗻:

If you worked with a team, talk about how you collaborated. What was your role in the team? How did you communicate and contribute to the team’s success?


➤ 𝗟𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝗮𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁:

Reflect on what you learned from the project. How did it help you grow professionally? What new skills did you gain, and what would you do differently next time?


➤ 𝗧𝗶𝗽𝘀 𝗳𝗼𝗿 𝗬𝗼𝘂𝗿 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗣𝗿𝗲𝗽𝗮𝗿𝗮𝘁𝗶𝗼𝗻:

Be ready with a 30-second elevator pitch about your projects, and also have a five-minute detailed overview ready.

Know why you chose the project, what your role was, what decisions you made, and how the results compared to what you expected.

Be clear on the scope of the project, whether it was a long-term effort or a quick task.

If there’s a pause after you describe the project, don’t hesitate to ask if they’d like more details or if there’s a specific part they’re interested in.


Remember, 𝗰𝗼𝗺𝗺𝘂𝗻𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗶𝘀 𝗸𝗲𝘆. You might have done great work, but if you don’t explain it well, it’s hard for the interviewer to understand your impact. So, practice explaining your projects with clarity.

By focusing on clear communication, you can showcase your skills more effectively and increase your chances of landing the job.

All the best 👍👍

Here is how you can explain your project in an interview 🔥

When you’re in an interview, it’s super important to know how to talk about your projects in a way that impresses the interviewer. Here are some key points to help you do just that:

➤ 𝗣𝗿𝗼𝗷𝗲𝗰𝘁 𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄:
- Start with a quick summary of the project you worked on. What was it all about? What were the main goals? Keep it short and sweet something you can explain in about 30 seconds.

➤ 𝗣𝗿𝗼𝗯𝗹𝗲𝗺 𝗦𝘁𝗮𝘁𝗲𝗺𝗲𝗻𝘁:
- What problem were you trying to solve with this project? Explain why this problem was important and needed addressing.

➤ 𝗣𝗿𝗼𝗽𝗼𝘀𝗲𝗱 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻:
- Describe the solution you came up with. How does it work, and why is it a good fix for the problem?

➤ 𝗬𝗼𝘂𝗿 𝗥𝗼𝗹𝗲:
- Talk about what you specifically did. What were your main tasks? Did you face any challenges, and how did you overcome them? Make sure it’s clear whether you were leading the project, a key player, or supporting the team.

➤ 𝗧𝗲𝗰𝗵𝗻𝗼𝗹𝗼𝗴𝗶𝗲𝘀 𝗮𝗻𝗱 𝗧𝗼𝗼𝗹𝘀:
- Mention the tech and tools you used. This shows your technical know-how and your ability to choose the right tools for the job.

➤ 𝗜𝗺𝗽𝗮𝗰𝘁 𝗮𝗻𝗱 𝗔𝗰𝗵𝗶𝗲𝘃𝗲𝗺𝗲𝗻𝘁𝘀:
- Share the results of your project. Did it make things better? How? Mention any improvements, efficiencies, or positive feedback you got. This helps show the project was a success and highlights your contribution.

➤ 𝗧𝗲𝗮𝗺 𝗖𝗼𝗹𝗹𝗮𝗯𝗼𝗿𝗮𝘁𝗶𝗼𝗻:
- If you worked with a team, talk about how you collaborated. What was your role in the team? How did you communicate and contribute to the team’s success?

➤ 𝗟𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝗮𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁:
- Reflect on what you learned from the project. How did it help you grow professionally? What new skills did you gain, and what would you do differently next time?

➤ 𝗧𝗶𝗽𝘀 𝗳𝗼𝗿 𝗬𝗼𝘂𝗿 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗣𝗿𝗲𝗽𝗮𝗿𝗮𝘁𝗶𝗼𝗻:
- Be ready with a 30 second elevator pitch about your projects, and also have a five-minute detailed overview ready.
- Know why you chose the project, what your role was, what decisions you made, and how the results compared to what you expected.
- Be clear on the scope of the project whether it was a long-term effort or a quick task.
- If there’s a pause after you describe the project, don’t hesitate to ask if they’d like more details or if there’s a specific part they’re interested in.

Remember, 𝗰𝗼𝗺𝗺𝘂𝗻𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗶𝘀 𝗸𝗲𝘆. You might have done great work, but if you don’t explain it well, it’s hard for the interviewer to understand your impact. So, practice explaining your projects with clarity.

By focusing on clear communication, you can showcase your skills more effectively and increase your chances of landing the job.

make sure to Scroll through the above messages 💞 you will definitely find more interesting things 💝

All the best 👍👍

Here are some of the hardest questions you might face in an interview.

Practice these using the 3-7-15 rule:

First solve the question, then note down the answer. After three days, try to remember the question from the answer and solve it again.

Repeat the same after 7 and 15 days.

This way, you'll solve the same question 4 times in 15 days, making it easier if you encounter it again.

1. Arrays & Strings

Minimum Window Substring

Trapping Rain Water

Largest Rectangle in Histogram


2. Linked Lists

Merge k Sorted Lists

Reverse Nodes in k-Group

LFU Cache


3. Trees

Binary Tree Maximum Path Sum

Serialize and Deserialize Binary Tree

Vertical Order Traversal of a Binary Tree


4. Dynamic Programming

Edit Distance

Burst Balloons

Shortest Common Supersequence


5. Graphs

Alien Dictionary

Minimum Cost to Make at Least One Valid Path in a Grid

Swim in Rising Water


6. Recursion & Backtracking

N-Queens II

Sudoku Solver

Word Search II


7. Sorting & Searching

Count of Smaller Numbers After Self

Median of Two Sorted Arrays

Split Array Largest Sum


8. Design

Design Search Autocomplete System

Design In-Memory File System

Design Excel Sum Formula


9. Greedy

Minimum Number of Arrows to Burst Balloons

Candy

Patching Array


10. Bit Manipulation

Maximum Product of Word Lengths

Smallest Sufficient Team

Minimum Cost to Connect Two Groups of Points


11. Two Pointers

Minimum Window Subsequence

Minimum Operations to Make a Subsequence

Minimum Adjacent Swaps to Reach the Kth Smallest Number


12. Heap

Minimum Number of Refueling Stops

Sliding Window Median

Minimum Number of K Consecutive Bit Flips


By following the 3-7-15 rule and practicing these tough questions regularly, you'll build strong problem-solving skills and be well-prepared for your interviews.

Keep pushing yourself, and remember, consistency is key.

Top Coding Interview Resources to prepare for Microsoft, Amazon, Meta, Apple, Adobe, VMware, Visa, Twitter, LinkedIn, JP Morgan, Goldman Sachs, Oracle, and Walmart:

t.me/addlist/XPgRhDouPTM3YWY1

All the best 👍👍

Most asked questions

➤ 𝗔𝗿𝗿𝗮𝘆𝘀 𝗮𝗻𝗱 𝗦𝘁𝗿𝗶𝗻𝗴𝘀:
1. Find the maximum sum subarray.
2. Find all substrings that are palindromes.
3. Implement the "two sum" problem.
4. Implement Kadane's algorithm for maximum subarray sum.
5. Find the missing number in an array of integers.
6. Merge two sorted arrays into one sorted array.
7. Check if a string is a palindrome.
8. Find the first non-repeating character in a string.
9. Write a program to remove duplicates from a sorted array.

1. Core Java Concepts
a. What is the difference between == and equals() method in Java?
b. Explain the concept of immutability. How is String class immutable?
c. How does garbage collection work in Java? What are different garbage collectors?
d. What are the different types of memory areas allocated by JVM?
e. How does hashCode() and equals() work?
f. What is the significance of final, finally, and finalize() in Java?
g. What is volatile keyword in Java?
h. What is the difference between HashMap and ConcurrentHashMap?