24/7 Customer Software Developer Intern Interview Questions and Answers

OnCampus Test including DSA Questions

Q1. Introduce yourself
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Q2. DSA Question based on Dynamic Programming
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Round duration - 60 minutes
Round difficulty - Medium

Round 1  was a coding round of 60 min which started around 5:30PM in which 2 problem statements were given. The questions were based on Array and linked list. The platform used for test was coding which was user friendly and which use to display number of test cases passed and some test cases were hidden.

Q1. 
Problem: Deletion in Circular Linked List
You are provided with a Circular Linked List of integers and a specific integer, referred to as 'key'.
Your task is to implement a function that locates the spec...read more
Ans. Recursion
The idea is to use a recursive approach to find the given key and then remove that node. The recursive idea is very clear that we will traverse through the circular linked list, and we will check if the value of the node is equal to the given key. 
 
We will define a function deleteNodeHelper(root, key, head) to remove the key in which the head is the starting node of the linked list, and we will send ...read more
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Q2. 
Rearrange Array: Move Negative Numbers to the Beginning
Given an array ARR consisting of N integers, rearrange the elements such that all negative numbers are located before all positive numbers. The orde...read more
Ans. Using Sorting
Approach: A brute force approach could be to just sort the given array in ascending order. This will result in all negative numbers to appear at the beginning and positive number at the end.
Space Complexity: O(1)Explanation:
O(1)
 
Because no extra space is required.
Time Complexity: O(nlogn)Explanation:
O(N*logN), where N is the number of elements in the array.
 
In the worst case, sorting requires O...read more
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Round duration - 30-35 minutes
Round difficulty - Medium

This round was of technical interview and they asked me various concepts

Round duration - 150 minutes
Round difficulty - Medium

It was an online round consisting of 2 programming questions restricted to C++, Java, and C# and 10 MCQ's on Data structures, Algorithms, etc..

Q1. 
Prime Time Again Problem Statement
You are given two integers DAY_HOURS and PARTS. Consider a day with DAY_HOURS hours, which can be divided into PARTS equal parts. Your task is to determine the total ins...read more
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Round duration - 60 minutes
Round difficulty - Easy

Q1. 
Find the Third Greatest Element
Given an array 'ARR' of 'N' distinct integers, determine the third largest element in the array.
Input:
The first line contains a single integer 'T' representing the numb...read more
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Round duration - 60 minutes
Round difficulty - Easy

Q1. Can you describe your projects and the tech stack you used in them?
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Round duration - 60 minutes
Round difficulty - Easy

Round duration - 90 Minutes
Round difficulty - Easy

It was a telephonic round. The interview asked me these questions.
 

Round duration - 60 Minutes
Round difficulty - Medium

The interviewer started asking me questions. He gave me 2 problems. He was giving hints in case of any issues.
 

Q1. 
Maximum Frequency Number Problem Statement
Given an array of integers with numbers in random order, write a program to find and return the number which appears the most frequently in the array.
If multip...read more
Ans. Brute Force Approach
Here, we can simply run two loops. The outer loop picks all elements one by one and the inner loop finds the frequency of the picked element and compares it with the maximum present so far.
 
Algorithm:
 
• Declare 4 variables as ‘maxFrequency’ , ‘currentFrequency’ , ‘maxElement’ , ‘currentElement’ and initialize them with 0
• Run a loop from ‘i’ = ‘0’ to ‘N’
  • Set ‘currentElement’ as arr[i] and ‘curr...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This was a technical interview. He gave me these questions one by one.
1. Again, how polymorphism works. Draw vtable and vptr
2. Producer consumer problem with synchronization
3. Difference between mutex, semaphore, and condition_variable.
4. Design parking lot system
5. Zigzag traversal of binary tree

Q1. Design a parking lot system.
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Q2. 
Zigzag Binary Tree Traversal Problem Statement
Determine the zigzag level order traversal of a given binary tree's nodes. Zigzag traversal alternates the direction at each level, starting from left to rig...read more
Ans. Iterative Approach
Our very basic intuition is that we are going to traverse the given binary tree using level order traversal where we just need to modify one thing that for every alternate level we need to reverse the order that level. 
 
Steps are as follows:
 
1. Create an empty queue.
2. For each node, first, the node is visited and then it’s child nodes are added in the queue if they exist(First in first out).
3. ...read more
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Round duration - 90 minutes
Round difficulty - Medium

1. He asked about the producer-consumer problem but I told him that the same question is asked in the previous round.
Then interviewer went asking lots of questions related to producer and consumer. Lots of discussions like what is a writer is not there and the only reader is there and you need to find out how many readers are currently reading from the buffer.
2. Discussions about C++11 features. How thread and async is different
3. Design your own shared_ptr(How you will handle ownership)
4. Check If the binary tree is symmetrical.
5. Find elements in a rotated sorted array and then optimize it.

Q1. 
Tree Symmetricity Problem Statement
You are provided with a binary tree structure, where each node consists of an integer value. Your task is to determine whether this binary tree is symmetric.
A symmetr...read more
Ans. Inorder And Reverse Inorder
We do two inorder traversals recursively of the tree simultaneously. For the first traversal, we traverse the left child first and then the right child, and in the second traversal, we traverse the right child first and then the left child. Let cur1 and cur2 be the current nodes of the first and second traversals respectively and initially both of them are passed as root. Then the algorithm f...read more
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Q2. 
Search In Rotated Sorted Array Problem Statement
Given a rotated sorted array ARR of size 'N' and an integer 'K', determine the index at which 'K' is present in the array.
Note:
1. If 'K' is not present...read more
Ans. Naive Approach
Naively traverse the array and find if ‘K’ is present in ARR or not. If ‘K’ is present in ARR return its index else return -1.
Space Complexity: O(1)Explanation:
O(1), i.e. constant space complexity. 
Time Complexity: O(n)Explanation:
O(N), where N is the length of the array/list. 
 
We are iterating over the array/list ARR once. Hence, the time complexity is O(N).

Java (SE 1.8)

/*

    Time Compl...read more
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Round duration - 90 minutes
Round difficulty - Easy

This round was scheduled for 9am in the morning. The test environment was pretty good . I didn't face any issues on the HireVeu platform. The first test was of Aptitude and then in next section it was Technical MCQ's. The level of questions were mid to high level of difficulty.

Round duration - 60 minutes
Round difficulty - Medium

The exam was on the same Platform. The first question was about the most difficult Project I've worked on. I have to record a video in that particular platform and then move to the next questions. There was option for a demo video of 1 minute in which you can practice your answers and then can record your answer in the next video of max 5 minutes. The next 2 question were Coding Problems of moderate difficulty and you've to record your approach and then proceed towards solving the code and then record a video stating if you succeed or not and what better could you've done to make it work.

Q1. 
Sum of N-Digit Palindromes
Determine the sum of all N-digit palindromes for a given integer 'N'. A palindrome is defined as a number that remains the same when its digits are reversed.
Example:
Input:
...read more
Ans. 
Run a loop from 10^(n-1) to 10^(n) – 1 and check when the current number is palindrome or not. If it is, adds its value to answer.
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Round duration - 45 minutes
Round difficulty - Medium

This round was scheduled for 3pm. The interviewer was quite friendly. He asked about me and told me to relax and then answer. He started with asking questions from my Project and how the ideas behind the Project. My Project was related to Deadlock So he asked whether I can implement my Project on any environment. I answered . Then one of my internship Project was related to Web development so He asked me about the backend of the Project. He gave me a few SQL queries and some general DBMS concepts based on the response about using Mysql in the Project. He asked me a few things about AWS and Cloud Computing which I answered. At last he asked some LINUX commands and corrected me once and was satisfied with my answers.