SquadStack Product Engineer Interview Questions, Process, and Tips

Round duration - 15 minutes
Round difficulty - Easy

They called around afternoon to know more about me. It happened over a phone call. Don't lie about anything as they do some screening. Asked reason for change.

Q1. Basic HR Questions
Are you ready to relocate?
Why do you want to join us?
What are your strengths?
 
Ans. 
Tip 1: Tell them honestly whatever is the reason
Tip 2:
Tip 3:
Answered by CodingNinjas
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Round duration - 150 minutes
Round difficulty - Medium

Asked 5 coding questions on DSA. Total marks were 250. Each question has a different weightage. They give you around a week to complete the round.

Q1. Left View Of Binary Tree
Given a binary tree. Print the Left View of the Tree.
Example :
If the input tree is as depicted in the picture: 
The Left View of the tree will be:  2 35 2 
Input format :
...read more
Ans. Recursive Approach
This problem can be solved through recursion.We will maintain max_level variable which will keep track of maxLevel and will pass current level in recursion as argument. Whenever we see a node whose current level is more than maxLevel then we will print that node as that will be first node for that current level. Also update maxLevel with current level.
Space Complexity: O(n)Explanation:
O(N), where ‘N’...read more
Answered by CodingNinjas
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Q2. Find Duplicates In Array
You are given an array/list 'ARR' consisting of N integers, which contains elements only in the range 0 to N - 1. Some of the elements may be repeated in 'ARR'. You...read more
Ans. Sorting
1. The most trivial approach would be to sort the array/list ‘ARR’ and then return the duplicates.
2. After sorting the array in non-decreasing order, do the following for all the elements from i = 0 to i = n - 2:
   • If ARR[i] == ARR[i + 1], then add ARR[i] to the the output list.
   • While ARR[i] == ARR[i + 1], do i = i + 1, since we don’t want to add the same duplicate elements again and again.
   • Else continue.
3. After this loop, w...read more
Answered by CodingNinjas
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Q3. Maximum Subarray Sum
Given an array of numbers, find the maximum sum of any contiguous subarray of the array.
For example, given the array [34, -50, 42, 14, -5, 86], the maximum sum would be 137, since w...read more
Ans. Brute Force Approach
1. Create a nested loop. The outer loop will go from i = 0 to i = n - k. This will cover the starting indices of all k-subarrays
2. The inner loop will go from j = i to j = i + k - 1. This will cover all the elements of the k-subarray starting from index i
3. Keep track of the maximum element in the inner loop and print it.
Space Complexity: O(1)Explanation:
O(1) because the extra space being used (looping vari...read more
Answered by CodingNinjas
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Q4. Longest Common Subsequence
You have been given two Strings “STR1” and “STR2” of characters. Your task is to find the length of the longest common subsequence.
A String ‘a’ is a subsequence of a String ‘b...read more
Ans. Recursive Brute Force
The basic idea of this approach is to break the original problem into sub-problems. Let us assume we want to find the length of the longest common subsequence of “STR1” and “STR2” whose length is ‘N’ and ‘M’ respectively. 
 
Now, let us define a recursive function 
 
LCS(Int I, int J, string STR1, string STR2)
Which returns the length of the longest common subsequence of string STR1...read more
Answered by CodingNinjas
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Q5. Reverse Words In A String
You are given a string of length N. You need to reverse the string word by word. There can be multiple spaces between two words and there can be leading or trailing spaces but in ...read more
Ans. Brute force
• Create a String ans to store the reversed string.
• Initialize a variable i to 0 and iterate the whole string through a while loop.
• Skip initial spaces by just incrementing i.
• Create a String that will store the current word.
• Add the currentword and space at the beginning of ans.
• After traversing the whole string, check if the length of ans is greater than 0 then return ans after removing the last space otherwise r...read more
Answered by CodingNinjas
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Round duration - 20 minutes
Round difficulty - Easy

Asks questions about your experience. Gives introduction to the role and what you'll be doing. Ask any questions about the company, culture or job.

Q1. Technical Question
Which tech stack have you worked on ?

 
Ans. 
Tip 1 : Just answer honestly. It doesn't matter if you have worked on a different tech stack than their job description
 
Answered by CodingNinjas
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Round duration - 120 minutes
Round difficulty - Medium

Q1. OOPS
Design a parking lot system.
Ans. 
Tip 1 : Write neat code with comments. Also write the readme to explain your code.
 
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Easy

Asked technical questions around DBMS and Java.

Q1. DBMS Question
What are ACID properties.
Ans. 
Tip 1 : Read about DBMS concepts.
Answered by CodingNinjas
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Q2. DBMS Question
What is an Inner Join?
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Round duration - 60 minutes
Round difficulty - Easy

2 coding questions were asked in this round. It was easier than the previous online coding round.

Q1. Arithmetic Expression Evaluation
You are given a string ‘expression’ consists of characters ‘+’, ‘-’, ‘*’, ‘/’, ‘(‘, ‘)’ and ‘0’ to ‘9’, that represents an Arithmetic Expression in Infix Notation. Your ...read more
Ans. 
1. Split the string with regex matching + sign
2. Thus, every element in the resultant String array has either a single number or an expression of products.
3. Now traverse through the array to find indices having products.
4. Split the product expression with regex matching * sign
5. Now multiply every number that was split using * sign in Step 4.
6. Finally, every index has only numbers that need to be added for the final...read more
Answered by CodingNinjas
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Q2. Covid Vaccination
We are suffering from the Second wave of Covid-19. The Government is trying to increase its vaccination drives. Ninja wants to help the Government to plan an effective method to help incr...read more
Ans. Brute force
The idea is to choose a peak value at the ‘dayNumber’ th index. Then we can create the array like a mountain with the peak of the mountain being at the  ‘dayNumber’ th index. The sum of the elements of this array must be less than or equal to maxVaccines.If we find that the sum is greater, then we have chosen a high peak value, and if it is less, then it means we have chosen a smaller peak value. So we ...read more
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Medium

It was a bar raiser round where they ask system design questions mostly around APIs and Databases.
Asked to create APIs and design tables.

Q1. System Design Question
They give a problem statement and ask to create different APIs according to the requirements. Also create db tables for the same. The APIs might need to join two tables.
Ans. 
Tip 1 : Read about APIs and Db design.
 
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Easy

Round with one of the founders to see for cultural fit. General questions about you, your journey, reason for change, priorities when looking for a job.

Q1. Basic HR Questions
What are the top 3 things you look for in a job?
Why do you want change?
 
Ans. 
Tip 1 : Don't lie and be honest. If you're not right for the company, then the company is also not right for you.
Tip 2 : Ask questions.
 
Answered by CodingNinjas
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Round duration - 30 minutes
Round difficulty - Easy

The round was a resume walkthrough and one question related to DS as I mentioned one project related to that.

It happened in the morning. You should walkthrough your resume before going for this round.

Q1. Technical Question
Since the round was a resume walkthrough, and they asked question related to the scale handling in the mentioned project
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Round duration - 60 minutes
Round difficulty - Medium

Round contained 1 DSA question

Q1. Factorial of a Number
You are given an integer ‘N’. You have to print the value of Factorial of ‘N’. The Factorial of a number ‘N’ is defined as the product of all numbers from 1 to ‘N’.
For Example:
Co...read more
Ans. 
Tip 1 : ease walkthrough the recursion tree that you are trying to think in your mind for this problem
 
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Easy

A problem based on data and I had to find some interference from the same

Q1. Data interpretation
The problem was focused on how you can make queries to find what the data is interpreting.
It was more of a discussion round to check how much you are good with the data
Ans. 
Tip 1 : Be open with your thoughts
 
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Easy

This was a culture fit round based on questions like why do you want to join a startup?
What do you expect working in a startup and how would you solve a challenge you are facing.
The career path that you are aiming

Q1. Technical Questions
Questions like 
Why do you want to join a start up?
What career path are you aiming for?
Any interesting problem that you have solved before.
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