Hitachi Digital Services Junior Software Engineer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Easy

This was a 60 minute technical round involving questions based on data structures, OOPS concepts, DBMS and projects that I had mentioned in my resume.

Q1. 
Nth Fibonacci Number Problem Statement
Calculate the Nth term in the Fibonacci sequence, where the sequence is defined as follows: F(n) = F(n-1) + F(n-2), with initial conditions F(1) = F(2) = 1.
Input:
...read more
Ans. 
Calculate the Nth Fibonacci number efficiently using recursion or dynamic programming.
• Implement a recursive function to calculate the Nth Fibonacci number.

• Use memoization to store previously calculated Fibonacci numbers for efficiency.

• Consider using dynamic programming to optimize the solution.

• Handle edge cases such as N = 1 or N = 2 separately.

• Ensure the solution works efficiently for large values of N (up to 10000).
Answered by AI
Add your answer
Q2. Can you provide a program demonstrating operator overloading in OOP?
Ans. 
Operator overloading in OOP allows custom behavior for operators like +, -, *, etc.
• Operator overloading is a feature in OOP that allows defining custom behavior for operators

• Example: Overloading the + operator to concatenate strings or add two numbers

• Example: Overloading the * operator to perform matrix multiplication
Answered by AI
Add your answer
Q3. What is function overloading?
Ans. 
Function overloading is when multiple functions have the same name but different parameters or return types.
• Allows multiple functions with the same name but different parameters or return types

• Helps improve code readability and maintainability

• Example: int add(int a, int b) and float add(float a, float b)
Answered by AI
Add your answer
Q4. What are the differences between C and C++?
Ans. 
C is a procedural programming language while C++ is a multi-paradigm programming language with object-oriented features.
• C is a procedural programming language while C++ supports both procedural and object-oriented programming.

• C does not support classes and objects while C++ does.

• C does not have built-in support for exception handling while C++ does.

• C does not have namespaces while C++ does.

• C does not have function over
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Easy

HR round that lasted for 45 minutes. Did brainstorming on puzzles and HR asked questions to know more about me.
Tips : During HR, think before you speak, they can catch any word that you speak. Prepare well for aptitude, as they shortlist less people after the test. Ask good questions during the end of the interviews. It might impress them. So prepare for it before going for the interview. Lastly, don’t be nervous, HRs are only trying to make you nervous during the interview as a part of the stress test.

Q1. How can you measure 45 minutes using two identical wires?
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

This was a 60 minute technical round where the interviewer asked programming based questions and questions on DBMS concepts.

Q1. 
Maximum of All Subarrays of Size k
Given an array of 'N' non-negative integers and an integer 'K', your task is to find the maximum elements for each subarray of size 'K'.
Input:
The first line contains...read more
Ans. 
Find the maximum elements for each subarray of size 'K' in an array of non-negative integers.
• Iterate through the array and maintain a deque to store the indices of elements in decreasing order.

• Pop elements from the deque if they are out of the current window of size 'K'.

• The front of the deque will always have the index of the maximum element in the current window.
Answered by AI
Add your answer
Q2. Can you explain the ACID properties in the context of database management systems?
Ans. 
ACID properties are a set of properties that guarantee the reliability of transactions in database management systems.
• Atomicity ensures that either all operations in a transaction are completed successfully or none of them are. For example, transferring money from one account to another should either be completed in full or not at all.

• Consistency ensures that the database remains in a consistent state before and after ...read more
Answered by AI
Add your answer
Q3. What is write-ahead logging in DBMS?
Ans. 
Write-ahead logging is a technique used in DBMS to ensure that changes are recorded in the log before they are applied to the database.
• Write-ahead logging ensures that changes are first written to the log file before being applied to the database to maintain data integrity.

• It helps in recovering the database in case of a system crash or failure by replaying the log entries to bring the database back to a consistent sta...read more
Answered by AI
Add your answer
Q4. What are the deadlock avoidance schemes?
Ans. 
Deadlock avoidance schemes are strategies used to prevent deadlocks in a system.
• Banker's algorithm: Ensures that the system will never enter an unsafe state by keeping track of available resources and only granting a request if it does not lead to a deadlock.

• Wait-die and Wound-wait: Two deadlock prevention schemes used in transaction processing systems to avoid deadlocks by allowing transactions to wait or abort based ...read more
Answered by AI
Add your answer
Q5. What is a clustered index?
Ans. 
A clustered index is a type of index that sorts and stores the data rows in the table based on their key values.
• Defines the order in which data is physically stored in a table

• Only one clustered index per table

• Helps in improving the performance of queries that involve range searches or sorting

• Example: Clustered index on a table's primary key
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

This was a 60 minute technical round where the interviewer asked data structure based questions, questions on OOPS and OS concepts.

Q1. What is a virtual function in C++?
Ans. 
A virtual function in C++ is a function that is declared within a base class and is redefined by a derived class.
• Virtual functions allow a function to be overridden in a derived class.

• They are used in polymorphism to achieve runtime binding.

• The base class function must be declared as virtual for dynamic binding to occur.

• Example: virtual void display() = 0; // pure virtual function
Answered by AI
Add your answer
Q2. Can you explain the malloc() and free() operations in the context of memory management in C?
Ans. 
malloc() is used to dynamically allocate memory in C, while free() is used to release allocated memory.
• malloc() allocates a block of memory of specified size and returns a pointer to the beginning of the block.

• free() deallocates the memory previously allocated by malloc() or calloc().

• Example: int *ptr = (int*)malloc(5 * sizeof(int)); // Allocates memory for 5 integers

• Example: free(ptr); // Deallocates the memory alloca
Answered by AI
Add your answer
Q3. What is structure padding?
Ans. 
Structure padding is the concept of adding empty bytes to a structure to align its data members on memory boundaries.
• Structure padding is done to optimize memory access and improve performance.

• Padding is necessary because most processors require data to be aligned on specific memory boundaries for efficient access.

• For example, if a structure contains a char followed by an int, padding may be added after the char to ali
Answered by AI
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

HR based round that lasted for 30 minutes. The interviewer asked question to know more about me.

Round duration - 90 minutes
Round difficulty - Easy

Online test had 6 parts-psychometric test, aptitude, logical, English, computer skills and 2 coding questions. Time given to us was 90 minutes. Paper was quite lengthy and of average difficulty level. I was able to complete all the sections, but only one coding question.

Q1. 
Reverse the String Problem Statement
You are given a string STR which contains alphabets, numbers, and special characters. Your task is to reverse the string.
Example:
Input:
STR = "abcde"
Output:
"e...read more
Ans. 
Reverse a given string containing alphabets, numbers, and special characters.
• Iterate through the string from the end to the beginning and append each character to a new string.

• Use built-in functions like reverse() or StringBuilder in languages like Python or Java for efficient reversal.

• Handle special characters and numbers while reversing the string.

• Ensure to consider the constraints provided in the problem statement.

• T...read more
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Firstly the interviewer asked me to introduce myself after he introduced himself. Since i went there as experienced guy he asked me about my workings in the current company. After that,he asked some programming questions, tested my concepts of DBMS and OOPS, and some puzzles.

Q1. 
BFS Traversal in a Graph
Given an undirected and disconnected graph G(V, E) where V vertices are numbered from 0 to V-1, and E represents edges, your task is to output the BFS traversal starting from the ...read more
Ans. 
BFS traversal in a disconnected graph starting from vertex 0.
• Implement BFS algorithm to traverse the graph starting from vertex 0.

• Explore neighbor nodes first before moving to the next level neighbors.

• Consider the bidirectional nature of edges in an undirected graph.

• Output the BFS traversal sequence for each test case in a separate line.
Answered by AI
Add your answer
Q2. 
Prime Numbers Identification
Given a positive integer N, your task is to identify all prime numbers less than or equal to N.
Explanation:
A prime number is a natural number greater than 1 that has no po...read more
Ans. 
Identify all prime numbers less than or equal to a given positive integer N.
• Iterate from 2 to N and check if each number is prime

• Use the Sieve of Eratosthenes algorithm for efficient prime number identification

• Optimize by only checking up to the square root of N for divisors
Answered by AI
Add your answer
Q3. What is BCNF (Boyce-Codd Normal Form) in database management systems?
Ans. 
BCNF is a normal form in database management systems that ensures all determinants are candidate keys.
• BCNF stands for Boyce-Codd Normal Form.

• It is a stricter version of 3NF (Third Normal Form).

• In BCNF, every determinant must be a candidate key.

• It helps in reducing redundancy and anomalies in the database.

• Example: If a table has columns A, B, and C, and A determines B and B determines C, then it is not in BCNF unless A
Answered by AI
Add your answer
Q4. What is the difference between C and C++?
Ans. 
C is a procedural programming language while C++ is an object-oriented programming language with features like classes and inheritance.
• C is a procedural programming language, while C++ is a multi-paradigm language with support for object-oriented programming.

• C does not support classes and objects, while C++ does.

• C uses structures for data organization, while C++ uses classes.

• C does not have features like inheritance an...read more
Answered by AI
Add your answer
Q5. How can you make 3 cuts to divide a round cake into 8 equal pieces?
Add your answer
Q6. How can you calculate 45 minutes using only 2 candles?
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

Again 2nd round started with an introduction from both sides. Then he started asking questions from resume itself. Working in the current company and all the projects that i have done. Few simple puzzles, OOPs concepts (with proper explanation and coding) and some database related questions(questions were easy you just need to brush up the basics). Some keywords related questions from C,C++,Java(usual questions like static ,final, abstract etc.). That was the 2nd round. Then I was called for the 3rd Round. Before 3rd round they also served tasty lunch.

Q1. 
Right View of Binary Tree
Given a binary tree of integers, your task is to output the right view of the tree.
The right view of a binary tree includes the nodes that are visible when the tree is observed...read more
Ans. 
The task is to output the right view of a binary tree, which includes the nodes visible when observed from the right.
• Traverse the tree level by level and keep track of the rightmost node at each level.

• Use a queue for level order traversal and a map to store the rightmost nodes.

• Print the values of the rightmost nodes stored in the map as the right view of the tree.
Answered by AI
Add your answer
Q2. You have 3 bulbs in one room and 3 switches in another room. The challenge is to determine which switch controls which bulb, with the constraint that you can only enter the bulb room once.
Add your answer

Round duration - 45 minutes
Round difficulty - Easy

After that he asked me what I knew about SAP and there products(Please do read all about SAP and there products-not all but at least some famous products like ERP). Then he asked me one puzzle.

Q1. You have 2 eggs and a building with 100 floors. What is the minimum number of attempts needed to find the highest floor from which an egg can be dropped without breaking?
Add your answer

Round duration - 45 minutes
Round difficulty - Easy

The round started with our Introduction to each other. After that interviewer asked me whether I do online shopping or not. I said yes then he asked me to design the online shopping portal using ER-Diagram . Then he asked me to create all the tables and populate it with data. Later on he asked me to normalize it. After all of this he asked me some simple puzzles and current salary and notice period. That was the 4th round.
After that I was asked to attend the final round and before 5th round they served snacks and tea to all of us.

Q1. Can you design an ER diagram for an online shopping portal?
Ans. 
Yes, I can design an ER diagram for an online shopping portal.
• Entities: User, Product, Order, Payment, Cart

• Relationships: User places Order, Order contains Product, Payment for Order, User has Cart

• Attributes: User (id, name, email), Product (id, name, price), Order (id, date), Payment (id, amount)
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

The test had a time limit. Every 10 minutes you had to do at least 4 questions. It was quite fast paced. The questions were from basic coding, aptitude and debugging.
Tips: Learn to be fast at coding. Practice a lot of aptitude questions. Have a decent knowledge of basic coding.

Q1. 
Reverse Linked List Problem Statement
Given a Singly Linked List of integers, your task is to reverse the Linked List by altering the links between the nodes.
Input:
The first line of input is an intege...read more
Ans. 
Reverse a singly linked list by altering the links between nodes.
• Iterate through the linked list and reverse the links between nodes

• Use three pointers to keep track of current, previous, and next nodes

• Update the next pointer of each node to point to the previous node
Answered by AI
Add your answer
Q2. 
Longest Substring Without Repeating Characters Problem Statement
Given a string S of length L, determine the length of the longest substring that contains no repeating characters.
Example:
Input:
"abac...read more
Ans. 
Find the length of the longest substring without repeating characters in a given string.
• Use a sliding window approach to keep track of the longest substring without repeating characters.

• Use a hashmap to store the index of each character as it appears in the string.

• Update the start index of the window when a repeating character is found.

• Calculate the maximum length of the substring as the window slides through the strin
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

The interviewer started off by asking basic sorting questions. Followed by data structures and algorithms. And DBMS related questions in the end.
Tips: Have a good presence of mind. Understand the question asked properly. Be confident and keep discussing. Don't get nervous and solve the questions incorrectly. Have good grip over topics like sorting, DS, Algorithms and DBMS.

Q1. 
LCA of Binary Tree Problem Statement
You are given a binary tree consisting of distinct integers and two nodes, X and Y. Your task is to find and return the Lowest Common Ancestor (LCA) of these two nodes...read more
Ans. 
Find the Lowest Common Ancestor (LCA) of two nodes in a binary tree.
• Traverse the binary tree to find the paths from the root to nodes X and Y.

• Compare the paths to find the last common node, which is the LCA.

• Handle cases where one node is an ancestor of the other.

• Consider edge cases like when X or Y is the root node.

• Implement a recursive or iterative solution to find the LCA efficiently.
Answered by AI
Add your answer
Q2. 
Next Permutation Problem Statement
You are given a permutation of 'N' integers. A sequence of 'N' integers is considered a permutation if it includes all integers from 1 to 'N' exactly once. Your task is ...read more
Ans. 
The task is to rearrange a given permutation of 'N' integers to form the lexicographically next greater permutation.
• Iterate from right to left to find the first element that is smaller than the element to its right.

• Swap this element with the smallest element to its right that is greater than it.

• Reverse the elements to the right of the swapped element to get the lexicographically next greater permutation.
Answered by AI
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

The round was based around my over all personality. They checked how would I be an asset to their company. They analyzed my core values and capabilities of working in a team.
Tips: Show that you are willing to work in a team. Be confident and polite. Express your feelings and passion towards your job and the company. Explain your college extra curricular activities well.

Round duration - 60 minutes
Round difficulty - Easy

This was a technical interview round which lasted for 60 minutes. Questions based on DSA, OS and DBMS were discussed.

Q1. 
Factorial of a Number Problem Statement
You are provided with an integer 'N'. Your task is to calculate and print the factorial of 'N'. The factorial of a number 'N', denoted as N!, is the product of all ...read more
Ans. 
Calculate and print the factorial of a given integer 'N'.
• Iterate from 1 to N and multiply each number to calculate factorial

• Handle edge cases like N=0 or N=1 separately

• Use recursion to calculate factorial efficiently
Answered by AI
Add your answer
Q2. 
Covid Vaccination Distribution Problem
As the Government ramps up vaccination drives to combat the second wave of Covid-19, you are tasked with helping plan an effective vaccination schedule. Your goal is...read more
Ans. 
Maximize the number of vaccines administered on a specific day while adhering to certain rules.
• Given n days, maxVaccines available, and a specific dayNumber, distribute vaccines to maximize on dayNumber

• Administer positive number of vaccines each day with a difference of 1 between consecutive days

• Ensure sum of vaccines distributed does not exceed maxVaccines

• Output the maximum number of vaccines administered on dayNumber
Answered by AI
Add your answer
Q3. What is a semaphore?
Ans. 
A semaphore is a synchronization construct used to control access to a shared resource by multiple processes or threads.
• Semaphores can have an integer value representing the number of available resources.

• They can be used to implement mutual exclusion and synchronization between processes.

• Examples include binary semaphores (mutexes) and counting semaphores.

• Operations on semaphores include wait (P) and signal (V).
Answered by AI
Add your answer
Q4. What is the difference between RDBMS and DBMS?
Ans. 
RDBMS is a type of DBMS that manages data in a structured format using tables with relationships.
• RDBMS enforces referential integrity through foreign keys, while DBMS does not.

• RDBMS supports ACID properties (Atomicity, Consistency, Isolation, Durability), while DBMS may not.

• RDBMS allows for normalization of data to reduce redundancy, while DBMS does not have this feature.

• Examples of RDBMS include MySQL, Oracle, SQL Ser...read more
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

A 60 minute technical round to test programming concepts. Questions on DBMS, OOPS, OS were also discussed.

Q1. 
Bubble Sort Problem Statement
Sort the given unsorted array consisting of N non-negative integers in non-decreasing order using the Bubble Sort algorithm.
Input:
The first line contains an integer 'T' r...read more
Ans. 
Bubble Sort algorithm is used to sort an array of non-negative integers in non-decreasing order.
• Iterate through the array and compare adjacent elements, swapping them if they are in the wrong order.

• Repeat this process until the array is sorted.

• Time complexity of Bubble Sort is O(n^2) in worst case.

• Space complexity of Bubble Sort is O(1) as it is an in-place sorting algorithm.
Answered by AI
Add your answer
Q2. 
Merge Sort Problem Statement
You are given a sequence of numbers, ARR. Your task is to return a sorted sequence of ARR in non-descending order using the Merge Sort algorithm.
Explanation:
The Merge Sort...read more
Ans. 
Implement Merge Sort algorithm to sort a sequence of numbers in non-descending order.
• Divide the input array into two halves recursively until each array has only one element.

• Merge the sorted halves to produce a completely sorted array.

• Time complexity of Merge Sort is O(n log n).

• Example: Input: [3, 1, 4, 1, 5], Output: [1, 1, 3, 4, 5]
Answered by AI
Add your answer
Q3. What is normalization in the context of database management systems?
Ans. 
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.
• Normalization involves breaking down a database into smaller, more manageable tables.

• It helps in reducing data redundancy by storing data in a structured way.

• There are different normal forms such as 1NF, 2NF, 3NF, BCNF, etc., each with specific rules to follow.

• Normalization ensures data integrity and reduces th...read more
Answered by AI
Add your answer

Round duration - 40 minutes
Round difficulty - Easy

This was a HR round. The interviewer asked me a number of questions about myself and gave a puzzle as well to solve.

Round duration - 100 minutes
Round difficulty - Easy

Sections in test :
1 Psychometric Test
2. Analytical Aptitude
3 Logical Reasoning
4 Two coding Questions
5.Pattern Recognition
6.Essay writing

Tips :

1. Do the coding Question first ,they are mot important ,if your code doesn't run you are disqualified.
2. Practice on leetcode. 
3. Sectional Cutoff

Q1. 
Level Order Traversal Problem Statement
Given a binary tree of integers, return the level order traversal of the binary tree.
Input:
The first line contains an integer 'T', representing the number of te...read more
Ans. 
The task is to implement a function that returns the level order traversal of a binary tree given in level order.
• Create a queue to store nodes for level order traversal

• Start with the root node and enqueue it

• While the queue is not empty, dequeue a node, print its value, and enqueue its children

• Repeat until all nodes are traversed
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

This was a technical round where the interviewer asked me questions on data structures, database management system, SQL queries, cloud computing concepts and puzzles. We also had a discussion on our projects.

Q1. 
Floyd Warshall Algorithm Problem
You are given a directed weighted graph with 'N' vertices, labeled from 1 to 'N', and 'M' edges. Each edge connects two nodes 'u' and 'v' with a weight 'w', representing t...read more
Ans. 
The Floyd Warshall algorithm is used to find the shortest paths between all pairs of vertices in a graph, including graphs with negative edge weights.
• The algorithm works by considering all pairs of vertices and all intermediate vertices to find the shortest path.

• It can handle graphs with negative edge weights, but not negative weight cycles.

• The time complexity of the algorithm is O(N^3), where N is the number of vertic...read more
Answered by AI
Add your answer
Q2. What would be the database design for an ATM system?
Ans. 
The database design for an ATM system should include tables for users, accounts, transactions, and ATM machines.
• Create a table for users with fields like user_id, name, pin, etc.

• Create a table for accounts with fields like account_id, user_id, balance, etc.

• Create a table for transactions with fields like transaction_id, account_id, amount, date, etc.

• Create a table for ATM machines with fields like atm_id, location, sta
Answered by AI
Add your answer
Q3. What is the difference between public and private cloud?
Ans. 
Public cloud is shared infrastructure available to anyone, while private cloud is dedicated infrastructure for a single organization.
• Public cloud is accessible to multiple organizations or users, while private cloud is exclusive to a single organization.

• Public cloud services are provided over the internet, while private cloud services can be hosted on-premises or in a dedicated data center.

• Public cloud offers cost-effe...read more
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round that lasted for 60 minutes. Questions on data structures, DBMS, OS and puzzles were discussed.

Q1. 
Reverse Linked List Problem Statement
Given a Singly Linked List of integers, your task is to reverse the Linked List by altering the links between the nodes.
Input:
The first line of input is an intege...read more
Ans. 
Reverse a singly linked list by altering the links between nodes.
• Iterate through the linked list and reverse the links between nodes

• Use three pointers to keep track of current, previous, and next nodes

• Update the links between nodes to reverse the list

• Return the head of the reversed linked list
Answered by AI
Add your answer
Q2. What is the difference between a primary key and a unique key in a database management system?
Ans. 
Primary key uniquely identifies each record in a table, while unique key ensures that all values in a column are distinct.
• Primary key does not allow NULL values, while unique key allows one NULL value.

• A table can have only one primary key, but multiple unique keys.

• Primary key is automatically indexed, while unique key may or may not be indexed.

• Example: In a table of students, student ID can be a primary key as it uniqu...read more
Answered by AI
Add your answer
Q3. Write a query to find the nth highest salary in a database.
Ans. 
Query to find the nth highest salary in a database
• Use the ORDER BY clause to sort salaries in descending order

• Use the LIMIT clause to specify the nth highest salary

• Consider handling cases where there may be ties for the nth highest salary
Answered by AI
Add your answer
Q4. What is the difference between AES and DES ciphers?
Ans. 
AES is a more secure and efficient cipher compared to DES.
• AES has a block size of 128 bits, while DES has a block size of 64 bits.

• AES supports key sizes of 128, 192, or 256 bits, while DES supports only 56-bit keys.

• AES is considered more secure and efficient than DES due to its stronger encryption algorithm and larger key sizes.
Answered by AI
Add your answer
Q5. You have a torch and a bridge that can only hold two people at a time. Four people need to cross the bridge at night, and they have only one torch. Each person walks at a different speed. When two people c...read more
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

The lady was tough and showed her intent in the PPT as well. She asked a number of questions to know more about me.

Round duration - 60 Minutes
Round difficulty - Medium

The interviewer asked me 2 questions related to DS/Algo in this round . Both the questions were of Easy-Medium difficulty and I was also required to code them in a production ready manner.

Q1. 
Maximum Sum Path in a Binary Tree Problem Statement
You are provided with a binary tree consisting of N nodes where each node has an integer value. The task is to determine the maximum sum achievable by a...read more
Ans. 
Find the maximum sum achievable by a simple path between any two nodes in a binary tree.
• Traverse the binary tree to find all possible paths and calculate their sums.

• Keep track of the maximum sum encountered during traversal.

• Consider paths that may include the same node twice.

• Implement a recursive function to explore all possible paths.

• Handle cases where nodes have negative values.
Answered by AI
Add your answer
Q2. 
Intersection of Two Arrays Problem Statement
Given two arrays A and B with sizes N and M respectively, both sorted in non-decreasing order, determine their intersection.
The intersection of two arrays in...read more
Ans. 
The problem involves finding the intersection of two sorted arrays efficiently.
• Use two pointers to iterate through both arrays simultaneously.

• Compare elements at the pointers and move the pointers accordingly.

• Handle cases where elements are equal, and update the intersection array.

• Return the intersection array as the result.
Answered by AI
Add your answer

Round duration - 50 Minutes
Round difficulty - Medium

This round had 2 questions of DS/Algo to solve under 50 minutes and one question related to Operating Systems.

Q1. 
Next Greater Element Problem Statement
You are provided with an array or list ARR containing N positive integers. Your task is to determine the Next Greater Element (NGE) for each element in the array.
T...read more
Ans. 
Find the Next Greater Element for each element in an array.
• Iterate through the array from right to left

• Use a stack to keep track of elements with no greater element to the right

• Pop elements from the stack until finding a greater element or stack is empty
Answered by AI
Add your answer
Q2. 
Number In Arithmetic Progression Problem
Given three integers X, C, and Y, where X is the first term of an arithmetic sequence with a common difference of C, determine if Y is part of this arithmetic sequ...read more
Ans. 
Check if a given number is part of an arithmetic sequence with a given first term and common difference.
• Calculate the arithmetic sequence using the formula: nth term = X + (n-1) * C

• Check if Y is equal to any term in the sequence to determine if it belongs to the sequence

• Return 'True' if Y belongs to the sequence, otherwise return 'False'
Answered by AI
Add your answer
Q3. Can you define process and threads in operating systems?
Ans. 
Processes are instances of programs in execution, while threads are smaller units within a process that can execute independently.
• A process is a program in execution, consisting of code, data, and resources.

• Threads are smaller units within a process that can execute independently.

• Processes have their own memory space, while threads share the same memory space within a process.

• Processes are heavyweight, while threads ar...read more
Answered by AI
Add your answer

Round duration - 50 Minutes
Round difficulty - Medium

This round had 2 questions of DSA of Easy-Medium difficulty and at the end I was asked a Puzzle to check my general problem solving ability.

Q1. 
Max Product Subset Problem Statement
Given an array/list arr of size n, determine the maximum product possible by taking any subset of the array/list arr. Return the result modulo 10^9+7 since the product ...read more
Ans. 
Find the maximum product of a subset of an array modulo 10^9+7.
• Iterate through the array and keep track of the maximum positive product and minimum negative product encountered so far.

• Handle cases where the array contains zeros separately.

• Return the maximum product modulo 10^9+7.
Answered by AI
Add your answer
Q2. 
Populating Next Right Pointers in Each Node
Given a complete binary tree with 'N' nodes, your task is to determine the 'next' node immediately to the right in level order for each node in the given tree.
...read more
Ans. 
Implement a function to update 'next' pointers in a complete binary tree.
• Iterate level by level using a queue

• Connect nodes at each level using 'next' pointers

• Handle null nodes appropriately

• Ensure the tree is a complete binary tree
Answered by AI
Add your answer
Q3. You have two wires of different lengths that are both capable of burning for exactly one hour when ignited at both ends. How can you measure a time interval of 45 minutes using these two wires?
Add your answer

Round duration - 50 Minutes
Round difficulty - Medium

This round consisted of 2 questions from DSA where I was first asked to explain my approach to the interviewer with proper complexity analysis and then code the problems. The interviewer was quite friendly and also provided me some hints when I was stuck.

Q1. 
Stack with getMin Operation
Create a stack data structure that supports not only the usual push and pop operations but also getMin(), which retrieves the minimum element, all in O(1) time complexity witho...read more
Ans. 
Implement a stack with push, pop, top, isEmpty, and getMin operations in O(1) time complexity without using extra space.
• Use two stacks - one to store the actual elements and another to store the minimum element at each level.

• When pushing an element, check if it is smaller than the current minimum and update the minimum stack accordingly.

• When popping an element, also pop from the minimum stack if the popped element is t...read more
Answered by AI
Add your answer
Q2. 
Split Array Into Maximum Subarrays Problem Statement
You are given an integer array arr of size N. Your task is to split the array into the maximum number of subarrays such that the first and last occurre...read more
Ans. 
Given an array, split it into maximum subarrays with first and last occurrence of each element in a single subarray.
• Iterate through the array and keep track of the first and last occurrence of each element.

• Use a hashmap to store the indices of each element.

• Split the array whenever the last occurrence of an element is found.
Answered by AI
Add your answer