Walstar Technologies Software Developer Interview Questions and Answers

Simple question on maths

Q1. Explain OOPS concept
Ans. 
OOPS (Object-Oriented Programming) is a programming paradigm based on the concept of objects, which can contain data and code.
• OOPS focuses on creating objects that interact with each other to solve complex problems

• Key principles include encapsulation, inheritance, polymorphism, and abstraction

• Encapsulation ensures that the internal state of an object is hidden from the outside world

• Inheritance allows a class to inherit...read more
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Q2. Coding array questions
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Easy to medium leetcode questions

Mcq + dsa JavaScript questions

Q1. JavaScript advance topics and database design topics
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Q1. Situation based question and behavioural questions
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Round duration - 30 minutes
Round difficulty - Medium

It was in the morning around 9:00Am-9:30AM. Platform used for this round was hacerrank. Questions were of moderate to difficult level.

Q1. 
Count Subarrays with Given XOR Problem Statement
You are given an array of integers ARR and an integer X. Your task is to determine the number of subarrays of ARR whose bitwise XOR is equal to X.
Example...read more
Ans. 
Count the number of subarrays in an array whose XOR is equal to a given value.
• Iterate through the array and keep track of XOR values and their frequencies using a hashmap.

• For each element in the array, calculate the XOR value with all previous elements and check if it equals the given XOR value.

• Use the concept of XOR to efficiently solve the problem.

• Handle edge cases like XOR value being 0 separately.

• Time complexity ca...read more
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Q2. 
Distinct Characters Problem Statement
Given a string STR, return all possible non-empty subsequences with distinct characters. The order of the strings returned is not important.
Example:
Input:
STR = ...read more
Ans. 
Return all possible non-empty subsequences with distinct characters from a given string.
• Iterate through all possible subsequences of the input string

• Check for distinct characters in each subsequence

• Return the distinct character subsequences as an array of strings
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Round duration - 15 minutes
Round difficulty - Easy

It was in the night around 8:00PM-8:20PM. Interviewer was very calm in questioning. Platform used for this round was Skype and the questions focused more on personality rather than total.

Round duration - 50 minutes
Round difficulty - Medium

Round duration - 20 minutes
Round difficulty - Medium

Q1. 
Pair Sum Problem Statement
You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.
Note:
...read more
Ans. 
Given an array and a target sum, find pairs of elements that add up to the target sum.
• Iterate through the array and for each element, check if the complement (target sum - current element) exists in a hash set.

• If the complement exists, add the pair to the result list. Otherwise, add the current element to the hash set.

• Sort the pairs based on the first element and then the second element to meet the required output form
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Round duration - 20 minutes
Round difficulty - Easy

Round duration - 40 minutes
Round difficulty - Hard

Q1. Can you provide an example of how to use pointers in C/C++ and discuss different concepts related to them?
Ans. 
Pointers in C/C++ are variables that store memory addresses. They are used to manipulate memory directly and improve performance.
• Pointers are declared using an asterisk (*) before the variable name.

• Pointers can be used to dynamically allocate memory using functions like malloc() and free().

• Pointers can be used to pass variables by reference to functions.
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1 hour online test ..

Q1. Programming related questions.
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Q1. DSA round (easy to medium)
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Q1. Technical+ hr round
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Q1. Technical questions.
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