FNZ Test Engineer Interview Questions and Answers

1 hour 10 mins, MERN Stack, Face to Face. Mongodb, medium DSA Question, callback, eventloop, NodeJS asynchronous working

2 questions. 1 was basic level. 2 was of medium level.

Q1. An ambiguous problem statement was given. Asking relevant questions revealed the problem to be largest island in a binary matrix. Was asked to code on an ide. And reduce space complexity to O(1).
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Q2. Maximum sum path from root to leaf in an N-ary tree. Was asked to design an appropriate data structure. Then code the solution in O(n) time and O(1) space.
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Q1. Through discuss of projects. Methods used.
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Q2. First missing positive number in an array of integer in O(n) time O(1) space.
Ans. 
Find first missing positive number in an array in O(n) time and O(1) space.
• Traverse the array and mark the presence of each positive integer by changing the sign of the corresponding index.

• Traverse the array again and return the index of the first positive integer.

• If all integers are present, return the length of the array + 1.

• Example: [3, 4, -1, 1] => mark 3rd and 4th index as negative => return 2.

• Example: [1, 2, 0] =...read more
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Q3. Given an integer, print the relevant column name in an excel sheet. Ex: 1- A , 2-B.......... 26-Z , 27-AA, 28-AB........ Was asked code on an ide and test cases were given.
Ans. 
Given an integer, print the relevant column name in an excel sheet.
• Create a string array of alphabets from A to Z

• Use modulo operator to get remainder and divide by 26 to get quotient

• Append the corresponding alphabet to the result string

• Reverse the result string
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Q1. What are your salary expectations?
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Maths,quant for 1 hour duration

Arrays, strings, linked list, palindrome

Round duration - 90 Minutes
Round difficulty - Medium

Q1. 
Cycle Detection in a Singly Linked List
Determine if a given singly linked list of integers forms a cycle or not.
A cycle in a linked list occurs when a node's next points back to a previous node in the ...read more
Ans. 
Detect if a singly linked list forms a cycle by checking if a node's next points back to a previous node.
• Use Floyd's Cycle Detection Algorithm to determine if there is a cycle in the linked list.

• Maintain two pointers, one moving at double the speed of the other, if they meet at any point, there is a cycle.

• If one of the pointers reaches the end of the list (null), there is no cycle.
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Q2. 
Next Greater Element Problem Statement
Given a list of integers of size N, your task is to determine the Next Greater Element (NGE) for every element. The Next Greater Element for an element X is the firs...read more
Ans. 
Find the Next Greater Element for each element in a list of integers.
• Iterate through the list of integers from right to left.

• Use a stack to keep track of elements for which the Next Greater Element is not yet found.

• Pop elements from the stack until a greater element is found or the stack is empty.

• Assign the Next Greater Element as the top element of the stack or -1 if the stack is empty.
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. How would you design an ATM machine?
Ans. 
Designing an ATM machine involves considering user interface, security measures, transaction processing, and hardware components.
• User interface should be intuitive and easy to navigate for users of all ages.

• Implement security measures such as PIN entry, card authentication, and encryption to protect user data.

• Transaction processing should be fast and reliable, with options for cash withdrawals, deposits, transfers, and...read more
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Round duration - 45 Minutes
Round difficulty - Easy