DataMetica Software Developer Interview Questions and Answers

Round duration - 30 minutes
Round difficulty - Medium

This was a MCQ round. 30 ques in 30 mins consisting of difficult quantitative aptitude questions were to be solved.

Round duration - 60 minutes
Round difficulty - Medium

In this test round, 2 coding questions were given. Either write the code or pseudo code

Q1. 
N Queens Problem
Given an integer N, find all possible placements of N queens on an N x N chessboard such that no two queens threaten each other.
Explanation:
A queen can attack another queen if they ar...read more
Ans. 
The N Queens Problem involves finding all possible placements of N queens on an N x N chessboard without threatening each other.
• Use backtracking algorithm to explore all possible configurations.

• Keep track of rows, columns, and diagonals to ensure queens do not threaten each other.

• Generate all valid configurations and print them out.
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Q2. 
Sort 0 1 2 Problem Statement
Given an integer array arr of size 'N' containing only 0s, 1s, and 2s, write an algorithm to sort the array.
Input:
The first line contains an integer 'T' representing the n...read more
Ans. 
Sort an array of 0s, 1s, and 2s in linear time complexity.
• Use three pointers to keep track of 0s, 1s, and 2s while traversing the array.

• Swap elements based on the values encountered to sort the array in-place.

• Time complexity should be O(N) and space complexity should be O(1).
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Round duration - 60 minutes
Round difficulty - Easy

This was a technical round with questions on DSA.

Q1. 
Reverse Words in a String: Problem Statement
You are given a string of length N. Your task is to reverse the string word by word. The input may contain multiple spaces between words and may have leading o...read more
Ans. 
Reverse words in a string while handling leading, trailing, and multiple spaces.
• Split the input string by spaces to get individual words

• Reverse the order of the words

• Join the reversed words with a single space in between
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Q2. 
Circular Linked List Detection
You are provided with the head of a linked list containing integers. Your task is to determine if the linked list is circular.
Note:
• A linked list is considered circula...read more
Ans. 
Detect if a given linked list is circular by checking if it forms a closed loop.
• Traverse the linked list using two pointers, one moving at double the speed of the other.

• If the two pointers meet at any point, the linked list is circular.

• If the faster pointer reaches the end of the list (NULL), the linked list is not circular.
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Round duration - 30 minutes
Round difficulty - Easy

HR round with typical behavioral problems.

Competitive coding, multiple choice questions

Q1. CS fundamentals, Object oriented programming, Networking, SQL
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Q2. Explain 4 concept of OOPS
Ans. 
OOPS concepts include Inheritance, Encapsulation, Polymorphism, and Abstraction.
• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the complex implementation details and showing only the necessary features.
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Q3. Explain subnet in networking
Ans. 
A subnet is a smaller network within a larger network, created by dividing the IP address range of the larger network.
• Subnets help in organizing and managing network resources efficiently.

• They allow for better security by isolating different parts of the network.

• Subnets can be created by dividing an IP address range into smaller ranges.

• For example, a company may have different subnets for different departments like HR,
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Q4. Concepts of Operating system
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Q1. Behavioral questions, questions related to project, questions related to internship
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It was an 1hr interview session

Q1. Find the occurrence of each element in an array
Ans. 
Count the occurrence of each element in an array of strings
• Iterate through the array and use a hashmap to store the count of each element

• If element already exists in the hashmap, increment its count by 1

• Return the hashmap with element counts
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Q1. Tell me about yourself
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Aptitude and coding of 2 hours

Q1. Questions based on sql and dsa
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Round duration - 120 minutes
Round difficulty - Medium

Timing was 9: 30 AM. Platform was quite good and easy to understand.

Q1. 
Reverse Only Letters Problem Statement
You are given a string S. The task is to reverse the letters of the string while keeping non-alphabet characters in their original position.
Example:
Input:
S = "...read more
Ans. 
Reverse the letters of a string while keeping non-alphabet characters in their original position.
• Iterate through the string and maintain two pointers, one at the start and one at the end, to reverse only the letters

• Use isalpha() function to check if a character is an alphabet or not

• Swap the letters at the two pointers until they meet in the middle
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Q2. 
Find Duplicates in an Array
Given an array ARR of size 'N', where each integer is in the range from 0 to N - 1, identify all elements that appear more than once.
Return the duplicate elements in any orde...read more
Ans. 
Find duplicates in an array of integers within a specified range.
• Iterate through the array and keep track of the count of each element using a hashmap.

• Return elements with count greater than 1 as duplicates.

• Time complexity can be optimized to O(N) using a set to store duplicates.

• Example: For input [0, 3, 1, 2, 3], output should be [3].
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Q3. 
Pancake Sorting Problem Statement
You are given an array of integers 'ARR'. Sort this array using a series of pancake flips. In each pancake flip, you need to:
Choose an integer 'K' where 1 <= 'K' <...read more
Ans. 
Sort an array using pancake flips and return the sequence of flips made.
• Iterate through the array and find the position of the maximum element in each iteration.

• Perform pancake flips to move the maximum element to the correct position.

• Continue this process until the array is sorted.

• Return the sequence of positions from where flips were made.
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Q4. 
Sum of Digits Problem Statement
Given an integer 'N', continue summing its digits until the result is a single-digit number. Your task is to determine the final value of 'N' after applying this operation ...read more
Ans. 
Given an integer, find the final single-digit value after summing its digits iteratively.
• Iteratively sum the digits of the given integer until the result is a single-digit number

• Output the final single-digit integer for each test case

• Handle multiple test cases efficiently
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Round duration - 30 minutes
Round difficulty - Medium

Timing was 9:30 AM. The interviewer was very nice.

Q1. 
Fibonacci Number Verification
Identify if the provided integer 'N' is a Fibonacci number.
A number is termed as a Fibonacci number if it appears in the Fibonacci sequence, where each number is the sum of...read more
Ans. 
Check if a given number is a Fibonacci number or not.
• Iterate through the Fibonacci sequence until you find a number greater than or equal to the given number.

• Check if the given number matches the Fibonacci number found in the sequence.

• If the number matches, output 'YES'; otherwise, output 'NO'.
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Q2. Write an SQL query to find the second highest salary from a table.
Ans. 
SQL query to find the second highest salary from a table
• Use the MAX() function to find the highest salary

• Use the WHERE clause to exclude the highest salary

• Order the salaries in descending order and limit the result to 1
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Round duration - 30 Minutes
Round difficulty - Medium

Timing was 12 PM. Interviewer was not good.

Q1. 
Character Frequency Problem Statement
You are given a string 'S' of length 'N'. Your task is to find the frequency of each character from 'a' to 'z' in the string.
Example:
Input:
S : abcdg
Output:
1...read more
Ans. 
The task is to find the frequency of each character from 'a' to 'z' in a given string.
• Create an array of size 26 to store the frequency of each character from 'a' to 'z'.

• Iterate through the string and increment the count of the corresponding character in the array.

• Print the array of frequencies as the output for each test case.
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Q2. What is normalization and can you explain the concept of Third Normal Form (3NF)?
Ans. 
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.
• Normalization is a technique used to organize data in a database efficiently.

• Third Normal Form (3NF) is a level of normalization that ensures that data is stored in a way that prevents certain types of data anomalies.

• In 3NF, every non-prime attribute is fully functionally dependent on the primary key.

• For exampl...read more
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Round duration - 120 minutes
Round difficulty - Easy

Timing was 9: 30 AM. Platform was quite good and easy to understand.

Q1. 
Reverse Only Letters Problem Statement
You are given a string S. The task is to reverse the letters of the string while keeping non-alphabet characters in their original position.
Example:
Input:
S = "...read more
Ans. 
Reverse the letters of a string while keeping non-alphabet characters in their original position.
• Iterate through the string and store the non-alphabet characters in their original positions

• Reverse the letters using two pointers technique

• Combine the reversed letters with the non-alphabet characters to get the final reversed string
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Q2. 
Find the Duplicate Number Problem Statement
Given an integer array 'ARR' of size 'N' containing numbers from 0 to (N - 2). Each number appears at least once, and there is one number that appears twice. Yo...read more
Ans. 
Find the duplicate number in an array of integers from 0 to N-2.
• Iterate through the array and keep track of the frequency of each number using a hashmap.

• Return the number with a frequency greater than 1 as the duplicate number.
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Q3. 
Reverse Array Elements
Given an array containing 'N' elements, the task is to reverse the order of all array elements and display the reversed array.
Explanation:
The elements of the given array need to...read more
Ans. 
Reverse the order of elements in an array and display the reversed array.
• Iterate through the array from both ends and swap the elements until the middle is reached.

• Use a temporary variable to store the element being swapped.

• Print the reversed array after all elements have been swapped.
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Q4. 
Sum of Digits Problem Statement
Given an integer 'N', continue summing its digits until the result is a single-digit number. Your task is to determine the final value of 'N' after applying this operation ...read more
Ans. 
Given an integer, find the final single-digit value after summing its digits iteratively.
• Iteratively sum the digits of the given integer until the result is a single-digit number

• Output the final single-digit integer for each test case

• Handle multiple test cases efficiently
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Round duration - 30 minutes
Round difficulty - Easy

Timing was 9:30 AM. The interviewer was very nice.

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 dynamic programming.
• Use dynamic programming to store and reuse previously calculated Fibonacci numbers.

• Start with base cases F(1) and F(2) as 1, then calculate subsequent Fibonacci numbers.

• Optimize the solution to avoid redundant calculations by storing intermediate results.

• Time complexity can be reduced to O(N) using dynamic programming.

• Example: For N = 5, the 5th F
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Q2. Write an SQL query to find the second highest salary from a table.
Ans. 
SQL query to find the second highest salary from a table
• Use the MAX() function to find the highest salary

• Use the NOT IN operator to exclude the highest salary from the results

• Order the results in descending order and limit the query to return only the second row
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Round duration - 30 minutes
Round difficulty - Medium

Timing was 12 PM. Interviewer was not good.

Q1. 
Character Frequency Problem Statement
You are given a string 'S' of length 'N'. Your task is to find the frequency of each character from 'a' to 'z' in the string.
Example:
Input:
S : abcdg
Output:
1...read more
Ans. 
The task is to find the frequency of each character from 'a' to 'z' in a given string.
• Create an array of size 26 to store the frequency of each character from 'a' to 'z'.

• Iterate through the string and increment the corresponding index in the array for each character encountered.

• Print the array of frequencies as the output for each test case.
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Q2. What is normalization and can you explain the concept of Third Normal Form (3NF)?
Ans. 
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.
• Normalization is a database design technique used to structure a relational database in a way that reduces data redundancy and improves data integrity.

• Third Normal Form (3NF) is a level of database normalization where every non-prime attribute of a table is dependent on the primary key.

• To achieve 3NF, a table m...read more
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