NEC Computer Operator and Programming Assistant Interview Questions and Answers

Round duration - 70 Minutes
Round difficulty - Medium

This round had 40 MCQ's followed by 2 questions of DS and Algo. The programming questions were preety standard and can be solved within 30 minutes.

Q1. 
Maximum Subarray Sum Problem Statement
Given an array arr of length N consisting of integers, find the sum of the subarray (including empty subarray) with the maximum sum among all subarrays.
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Ans. 
Find the sum of the subarray with the maximum sum among all subarrays in a given array.
• Iterate through the array and keep track of the maximum sum subarray seen so far.

• Use Kadane's algorithm to efficiently find the maximum subarray sum.

• Handle cases where all elements are negative or array is empty.

• Example: For input arr = [-2, 1, -3, 4, -1], the maximum subarray sum is 4.
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Q2. 
Remove Character from String Problem Statement
Given a string str and a character 'X', develop a function to eliminate all instances of 'X' from str and return the resulting string.
Input:
The first lin...read more
Ans. 
Develop a function to remove all instances of a given character from a string.
• Iterate through the string character by character and only add characters that are not equal to the given character to a new string.

• Alternatively, use built-in string manipulation functions to remove all instances of the given character from the string.

• Ensure the function handles edge cases such as empty strings or strings with no instances o...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This round had questions from DSA, OS, DBMS and Computer Networks. The programming question was quiet easy and I coded it preety fast after discussing the appropriate approach and complexity analysis.

Q1. 
Intersection of Linked List Problem
You are provided with two singly linked lists containing integers, where both lists converge at some node belonging to a third linked list.
Your task is to determine t...read more
Ans. 
Find the node where two linked lists merge, return -1 if no merging occurs.
• Traverse both lists to find their lengths and the difference in lengths

• Move the pointer of the longer list by the difference in lengths

• Traverse both lists simultaneously until they meet at the merging point
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Q2. Can you explain the concepts of multitasking and multiprogramming?
Ans. 
Multitasking involves executing multiple tasks simultaneously, while multiprogramming involves running multiple programs on a single processor.
• Multitasking allows multiple tasks to run concurrently on a single processor, switching between them quickly.

• Multiprogramming involves loading multiple programs into memory and executing them concurrently, utilizing idle CPU time efficiently.

• Examples of multitasking include runn...read more
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Q3. What is the difference between a process and a program?
Ans. 
A process is an executing instance of a program, while a program is a set of instructions stored in the computer's memory.
• A program is a static set of instructions stored on disk, while a process is a dynamic instance of those instructions being executed in memory.

• Multiple processes can be running the same program simultaneously, each with its own memory space and resources.

• Processes have their own unique process ID (P...read more
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Q4. What is the difference between a process and a thread?
Ans. 
A process is an instance of a program, while a thread is a unit of execution within a process.
• A process has its own memory space, while threads share the same memory space.

• Processes are independent and isolated, while threads can communicate and share resources.

• Creating a new process is more resource-intensive than creating a new thread.

• Processes have their own program counter, while threads share the same program coun...read more
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Q5. What is the main difference between UNION and UNION ALL?
Ans. 
UNION combines and removes duplicate rows, UNION ALL combines without removing duplicates.
• UNION combines the result sets of two or more SELECT statements into a single result set

• UNION removes duplicate rows from the result set

• UNION ALL combines the result sets without removing duplicates

• UNION is slower than UNION ALL as it requires additional processing to remove duplicates

• Use UNION when you want to combine and remove ...read more
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Q6. What are the advantages of using views in a database management system?
Ans. 
Views provide a virtual representation of data, offering advantages such as simplifying complex queries, enhancing security, and improving performance.
• Views simplify complex queries by predefining commonly used joins, filters, and aggregations.

• Views enhance security by allowing users to access only specific columns or rows of a table.

• Views improve performance by storing the results of complex queries, reducing the need...read more
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Q7. What is the ARP protocol?
Ans. 
ARP stands for Address Resolution Protocol, used to map IP addresses to MAC addresses in a local network.
• ARP is used to find the MAC address of a device based on its IP address

• It operates at the data link layer of the OSI model

• ARP requests are broadcasted to all devices on the local network

• Example: When a device wants to communicate with another device on the same network, it uses ARP to find the MAC address of the des
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Round duration - 30 Minutes
Round difficulty - Easy

This is a cultural fitment testing round. HR was very frank and asked standard questions. Then we discussed about my role.

Q1. Why should we hire you?
Ans. 
I should be hired because of my strong technical skills, problem-solving abilities, and passion for software development.
• I have a solid understanding of data structures and algorithms.

• I have experience in developing and debugging complex software systems.

• I am a quick learner and can adapt to new technologies and programming languages.

• I have a track record of delivering high-quality code on time.

• I am a team player and c...read more
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Q2. What is something about you that is not included in your resume?
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