Walmart IN3 | March | Full stack Developer |

I was contacted by a consultancy about a potential job opportunity.

The first round of the interview focused on problem-solving and backend-related discussion.

• Introduction, current project, current tech stack, knowledge/familiarity of Java as I didn't have any work experience in Java.
• Three Sum problem. Detailed discussion on how the optimized version would be O(n^2), not O(n^3). The interviewer was looking for big O notation and how these complexities are calculated, the fundamentals about various kinds of complexities.
• Count number of leaves in a binary tree.
• Table1: name,loc,datetime abc,india,0419 xyz,us,0512 bbb,india,0101 ccc,mexico,0105 zzz,india,0406 sss,us,0420

Table2: name,loc,datetime abc,india,0419 xyz,uk,0111

//Write a SQL query to select de-duplicated records (from the combination of above 2 tables) based on “loc” with highest “datetime” // //Final output/result should have only one record per location (with its own highest datetime) // //Output will be: // name,loc,datetime abc,india,0419 xyz,us,0512 ccc,mexico,0105 xyz,uk,0111

I couldn't figure out the complete query by myself, but the interviewer helped, and this was the answer we both came to agree on - Select Table.name, Table.loc, Table.datetime from (Select * from Table1 UNION Table2) Table where DENSE_RANK(loc) = 1 PARTITION BY loc ORDER BY datetime;

The second round of the interview focused on problem-solving and front-end related discussion.

• Introduction, front-end experience, Familiarity with front-end frameworks, Javascript, ES6.
• Trapping rain water problem, approach and pseudo code.
• Design patterns which I have used. Explain builder pattern with example.
• Webpack, and how it works.
• Dependency injection.
• Closure.
• DOM Manipulation.
• Virtual DOM Manipulation in React.
• Rendering cache.
• Variable hoisting.
• Treeshaking.
• Web workers, I didn't know, but I mentioned service workers which I explained well.
• Web components.
• Difference between var and let.
• Difference between functional programming and object-oriented programming.
• Node JS internal architecture. How does it work asynchronously.
• React hooks.
• Various ways of code optimization methods.
• Any questions.

Result: Waiting for the second round response.