Tracxn Full Stack Developer Interview Questions and Answers

Data Structures, Coding MCQs

Q1. What is Data Structure
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Q2. Write DFS Algorithm
Ans. 
Depth-First Search (DFS) is a graph traversal algorithm that explores as far as possible along each branch before backtracking.
• DFS uses a stack data structure, either explicitly or via recursion.

• It starts from a selected node and explores each branch before backtracking.

• Example: In a binary tree, DFS can be implemented using pre-order, in-order, or post-order traversal.

• DFS can be used to find connected components in a ...read more
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Easy to medium questions, Questions on DSA and Node.js.

Q1. Valid parenthesis
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Q2. Three sum problem
Ans. 
The three sum problem involves finding unique triplets in an array that sum to zero.
• Sort the array to simplify finding triplets.

• Use a loop to fix one element and apply two-pointer technique for the rest.

• Skip duplicates to ensure unique triplets.

• Example: For array [-1, 0, 1, 2, -1, -4], the triplets are [-1, -1, 2], [-1, 0, 1].
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Basic coding only not to worry much

Q1. Tell me about ur self
Ans. 
I am a passionate software developer with experience in Java, Python, and web development.
• Experienced in Java, Python, and web development technologies

• Strong problem-solving skills

• Excellent team player with good communication skills
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Q2. What is ur projects
Ans. 
I have worked on various projects including a web-based inventory management system and a mobile app for tracking fitness goals.
• Developed a web-based inventory management system using React and Node.js

• Created a mobile app for tracking fitness goals using Flutter

• Implemented RESTful APIs for communication between frontend and backend systems
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Easy level to Medium level

2 Easy questions of DSA

Q1. One DSA question
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Q2. Normal discussion about tech stack
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Q1. Tell about yourself
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Q2. Why do you want to join digit?
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The exam duration is one and a half hours.

The total exam time is one and a half hours.

It encompasses all topics related to full stack development.

Q1. Asks questions on SQL
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Q2. Asks question in typical topics
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Q1. Where do you see yourself in two years?
Ans. 
In two years, I see myself as a senior software developer leading a team on innovative projects.
• Advancing to a senior software developer role

• Leading a team on new and innovative projects

• Continuing to enhance my technical skills through ongoing learning and training
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Sorting of an array and aptitude

Q1. BFS graph traversal
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Q1. Binary tree question
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Q1. Explain Deadlock?
Ans. 
Deadlock is a situation in computing where two or more processes cannot proceed because each is waiting for the other to release resources.
• Occurs in multi-threaded environments when processes hold resources and wait for others.

• Example: Process A holds Resource 1 and waits for Resource 2, while Process B holds Resource 2 and waits for Resource 1.

• Can lead to system inefficiency and unresponsiveness.

• Deadlock detection and...read more
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Q2. Explain Red Black Tree?
Ans. 
A Red-Black Tree is a balanced binary search tree with specific properties to ensure efficient operations.
• Each node is colored either red or black.

• The root node is always black.

• Red nodes cannot have red children (no two reds in a row).

• Every path from a node to its descendant leaves must have the same number of black nodes.

• This structure ensures O(log n) time complexity for insertion, deletion, and search operations.

• Exa...read more
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Q3. Find local minima in a 1-D array?
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Q4. Find local minima in 2-D array?
Ans. 
Local minima in a 2-D array are elements smaller than their neighbors. We can find them using various algorithms.
• A local minimum is defined as an element that is less than its adjacent elements.

• For example, in the array [[9, 8, 7], [6, 5, 4], [3, 2, 1]], the element 1 is a local minimum.

• To find local minima, iterate through each element and compare it with its neighbors (up, down, left, right).

• Consider edge cases where...read more
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Round duration - 75 minutes
Round difficulty - Medium

The test had 3 questions which had to solved in 75 minutes.The test was of medium difficulty.

Q1. 
Meeting Rooms Allocation Problem Statement
Stark Industry is planning to organize meetings for various departments in preparation for Stark Expo. Due to limited rooms in Stark Tower, the goal is to alloca...read more
Ans. 
Determine the minimum number of conference rooms needed to schedule meetings without overlap.
• Sort the meetings by start time.

• Iterate through the meetings and keep track of the rooms in use.

• If a meeting starts after another ends, it can reuse the same room.

• If a meeting starts before another ends, a new room is needed.

• Return the maximum number of rooms in use at any point.
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Q2. 
Maximize XOR Value
You are provided with an integer X and are tasked with identifying an integer Y such that the bitwise XOR operation between X and Y yields the maximum possible value. The condition is t...read more
Ans. 
Find an integer Y such that XOR operation with X yields maximum value within given constraints.
• Iterate from the most significant bit to find the highest bit that can be toggled to maximize XOR value.

• To maximize XOR value, toggle the highest bit of X to 0 and all lower bits to 1.

• Ensure the final Y does not exceed (2^61) - 1.

• Example: For X = 3, the highest bit to toggle is at position 61, so Y = 2305843009213693950.

• Examp...read more
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Q3. 
Minimize Maximum Difference Between Adjacent Elements
You are provided with a non-decreasing array and an integer K. Your task is to remove exactly K elements from this array so that the maximum differenc...read more
Ans. 
Remove K elements from a non-decreasing array to minimize the maximum difference between adjacent elements.
• Sort the array in non-decreasing order.

• Iterate through the array and calculate the difference between adjacent elements.

• Remove elements to minimize the maximum difference.

• Return the minimized maximum difference.
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Round duration - 60 minutes
Round difficulty - Easy

The interview was taken by SDE2 and she was very friendly. All the questions asked were related to DS and algo. The first 10 minutes were used for introductions and the last 5 minutes were reserved for any questions that I have. Always try to ask meaningful questions at the end of the interview.

Q1. 
Frequency in a Sorted Array Problem Statement
Given a sorted array ARR and a number X, your task is to determine the count of occurrences of X within ARR.
Note:
• If X is not found in the array, return...read more
Ans. 
Count occurrences of a number in a sorted array efficiently.
• Use binary search to find the first and last occurrence of the target number in the array.

• Calculate the count of occurrences by subtracting the indices of the last and first occurrences.

• Handle cases where the target number is not found in the array.

• Time complexity: O(log(N)), Space complexity: O(1).
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Q2. 
Rotting Oranges Problem Statement
You are given a grid containing oranges where each cell of the grid can contain one of the three integer values:
• 0 - representing an empty cell
• 1 - representing a fre...read more
Ans. 
Find the minimum time required to rot all fresh oranges in a grid.
• Use Breadth First Search (BFS) to simulate the rotting process

• Track the time taken to rot all oranges and return -1 if any fresh oranges remain

• Handle edge cases such as no fresh oranges or all oranges already rotten

• Consider using a queue to efficiently process neighboring oranges
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Q3. 
Clone Linked List with Random Pointer Problem Statement
Given a linked list where each node has two pointers: one pointing to the next node and another which can point randomly to any node in the list or ...read more
Ans. 
Yes, the cloning of a linked list with random pointer can be accomplished without utilizing extra space.
• Use a hashmap to store the mapping between original nodes and cloned nodes.

• Iterate through the original linked list to create the cloned linked list by mapping the random pointers using the hashmap.

• Time complexity of this approach is O(N) where N is the number of nodes in the linked list.
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Round duration - 60 minutes
Round difficulty - Medium

The focus of this round was mainly on my projects and internships. It was taken by a Senior SDE and it more of a technical interaction. I was asked in-depth about my projects and most of the questions asked around OS/DBMS were based on my projects.
The interviewer wanted to judge whether I have core knowledge about subjects like OS and DBMS and also about the projects that I had done.

Round duration - 60 minutes
Round difficulty - Easy

It was the culture fit round taken by the Director of Engineering.