Data Scientist Interview Questions

Dhruv S. - "Before proceeding, I just wanted to clarify we wanted to check for the impact of showing content from non-friends in users’ feeds, and here non-friends I would assume could be anyone, but mainly like content creators, and I am not including ads here. But I wanted to ask if there is any current logic as to what posts to show based on users' affinity to those posts, maybe basis the user engagement to Insta feed. now objective of this would be to improve the engagement of the platform, as if users"See full answer

Umang S. - "Context - I joined a large public-facing service as a PM midway through its development. Situation - Due to the SOPs of the company the team already had a metrics framework. That included your standard DAUs, Retention and Acquisition Metrics Concern - As SOP metrics were publicly accepted, the team did not internalise what success actually means to the product they are developing, as the actual value was not being encapsulated in the framework This was evident in the show and tells as the"See full answer

Abhinav M. - "Always assume good intentions on the part of both parties when resolving conflicts. Then proceed with a STAR example."See full answer

VContaineers - " Compare alternate houses i.e for each house starting from the third, calculate the maximum money that can be stolen up to that house by choosing between: Skipping the current house and taking the maximum money stolen up to the previous house. Robbing the current house and adding its value to the maximum money stolen up to the house two steps back. package main import ( "fmt" ) // rob function calculates the maximum money a robber can steal func maxRob(nums []int) int { ln"See full answer

Kishor J. - "we can use two pointer + set like maintain i,j and also insert jth character to set like while set size is equal to our window j-i+1 then maximize our answer and increase jth pointer till last index"See full answer

Temesgen B. - "Very Good Explanation Thanks For This Rely Good Explanation"See full answer

Anonymous Prawn - "Would be better to adjust resolution in the video player directly."See full answer

Bradley E. - "Here's a simpler solution: select u.username , count(p.postid) as countposts from posts as p join users as u on p.userid = u.userid where p.likes >= 100 group by 1 order by 2 desc, 1 asc limit 3 `"See full answer

Vysali K. - "Limit and rank() only works if there are no 2 employees with same salary ( which is okay for this use case) For the query to pass all the test results, we need to use dense_rank with ranked_employees as ( select id, firstname, lastname, salary, denserank() over(order by salary desc) as salaryrank from employees ) select id, firstname, lastname, salary from ranked_employees where salary_rank <= 3 `"See full answer

Bala G. - "WITH ActiveUsersYesterday AS ( SELECT DISTINCT user_id FROM user_activity WHERE activity_date = CAST(GETDATE() - 1 AS DATE) ), VideoCallUsersYesterday AS ( SELECT DISTINCT user_id FROM video_calls WHERE call_date = CAST(GETDATE() - 1 AS DATE) ) SELECT (CAST(COUNT(DISTINCT v.userid) AS FLOAT) / NULLIF(COUNT(DISTINCT a.userid), 0)) * 100 AS percentagevideocall_users FROM ActiveUsersYesterday a LEFT JOIN VideoCallUsersYesterday v ON a.userid = v.userid;"See full answer

Gaston B. - "Use a representative of each, e.g. sort the string and add it to the value of a hashmap> where we put all the words that belong to the same anagram together."See full answer

Bhavna S. - "Before diving into the Solution, I would ask a few clarifying questions. What is the scope of the fake news What type of fake news are we focusing on - Political, Health-related, etc Are we looking at specific examples or a general category of fake news When you say impact, what do you mean by that? Is it time spent on posts, the nature of the engagement (e.g., likes, shares, comments), and the sentiment of the comments? User Demographics: what is the demographic pr"See full answer

Anonymous Possum - "#inplace reversal without inbuilt functions def reverseString(s): chars = list(s) l, r = 0, len(s)-1 while l < r: chars[l],chars[r] = chars[r],chars[l] l += 1 r -= 1 reversed = "".join(chars) return reversed "See full answer

Anisha S. - "SELECT d.name as departmentname,e.id as employeeid,e.firstname,e.lastname,MAX(e.salary) as salary FROM employees e LEFT JOIN departments d ON e.department_id=d.id GROUP BY department_name ORDER BY department_name;"See full answer

Vishal S. - "Product Understanding - Ads are what you see from companies as stories, posts, reels. Post are from users (connections). We have to design an experience which produces maximum engagement while generating ad revenue. Clarifying Questions - Is it specific to posts/stories/reels ? Is there an existing post to ads ratio or do we have to start from scratch? Is it specific to a device/OS? Is it specific to a region/user demographic? Assumption - Existing posts to ads ratio"See full answer

Tiago R. - "function isValid(s) { const stack = []; for (let i=0; i < s.length; i++) { const char = s.charAt(i); if (['(', '{', '['].includes(char)) { stack.push(char); } else { const top = stack.pop(); if ((char === ')' && top !== '(') || (char === '}' && top !== '{') || (char === ']' && top !== '[')) { return false; } } } return stack.length === 0"See full answer

Akshay D. - "SELECT u.user_id, u.user_name, u.email, ROUND(AVG(CASE WHEN b.status = 'Unmatched' THEN 1.0 ELSE 0 END), 2) AS avgunmatchedbookings FROM users u LEFT JOIN bookings b ON u.userid = b.userid GROUP BY u.user_id, u.user_name, u.email; `"See full answer

Vineet M. - "Precision - Out of all the things we picked as correct, how many were actually correct? recall - Out of all the things that were truly correct, how many did we actually find?"See full answer

Bhavna S. - "Step 1: Define Objectives and Key Metrics Objectives: Understand the demand for group video calling. Assess the potential impact on user engagement. Identify technical and user experience considerations. Key Metrics: Call Frequency: Number of 1:1 calls per user. Call Duration: Average duration of 1:1 calls. Call Participants: Identify users who frequently call multiple individuals. Concurrent Calls: Instances where users are engaged in multiple 1:1 call"See full answer

Evan R. - "The user table no longer exists as expected - I get an error that user does not contain user_id. Note that querying the table results in only user:swuoevkivrjfta select * FROM user `"See full answer