Biofourmis Quality Analyst Interview Questions and Answers

Computer Fundamentals

Q1. Flatten a binary tree
Ans. 
Flatten a binary tree by converting it into a linked list in-place.
• Use a recursive approach to flatten the binary tree.

• Traverse the tree in a pre-order manner and keep track of the previous node.

• Set the left child of each node to null and the right child to the next node in the linked list.

• Example: Input: 1 -> 2 -> 5 -> 3 -> 4 -> null, Output: 1 -> null -> 2 -> null -> 3 -> null -> 4 -> null -> 5 -> null
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Q1. What is a multithreaded environment, and how would you develop an application that can run in that environment without any issues?
Ans. 
A multithreaded environment allows multiple threads to execute concurrently, improving application performance and responsiveness.
• Thread Management: Use thread pools to manage threads efficiently, reducing overhead from frequent thread creation and destruction.

• Synchronization: Implement synchronization mechanisms (like mutexes or semaphores) to prevent race conditions when accessing shared resources.

• Concurrency Control...read more
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Q2. What locking mechanisms are used in a multithreaded environment to prevent deadlock in critical sections?
Ans. 
Locking mechanisms in multithreaded environments prevent deadlock by managing access to critical sections effectively.
• Mutexes: A mutual exclusion lock that allows only one thread to access a resource at a time, preventing race conditions.

• Semaphores: A signaling mechanism that controls access to a resource by maintaining a count, allowing multiple threads to access it up to a limit.

• Read/Write Locks: These allow multiple...read more
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Round duration - 90 minutes
Round difficulty - Hard

Timing was late evening. Platform was good.

Q1. 
Largest Cycle in Maze Problem Statement
Given a maze represented by 'N' cells numbered from 0 to N-1, and an array arr of 'N' integers where arr[i] denotes the cell number that can be reached from the 'i'...read more
Ans. 
Identify the length of the largest cycle in a maze represented by cells and an array of integers.
• Iterate through each cell and find the cycle length using DFS or Floyd's Tortoise and Hare algorithm.

• Handle self-cycles and cells with no exit by checking arr[i] = i and arr[i] = -1 respectively.

• Output the length of the largest cycle found or -1 if no cycles exist.
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Q2. 
Ninja and the Maze Problem Statement
Ninja is stuck in a maze represented as a 2D grid. He can move in four directions (Up, Down, Left, Right) until he hits a wall ('1'). Once stopped, he can choose a new...read more
Ans. 
Determine if Ninja can reach the destination in a maze by moving in four directions until hitting a wall.
• Create a function to traverse the maze using depth-first search or breadth-first search.

• Keep track of visited cells to avoid infinite loops.

• Return 'True' if destination is reachable, 'False' otherwise.
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There are some 15 qstions objective types.

Q1. Test cases on logout. Q2. Self join Q3. Api
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Q1. Explain ur project
Ans. 
Developed a web application for online shopping with features like user authentication, product search, and order tracking.
• Used Selenium for automated testing of user authentication process

• Implemented RESTful APIs for product search functionality

• Utilized JUnit for unit testing of order tracking feature
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Q1. Api testing, db testing
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Q1. Salary discussion
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Q1. Select 10 recods with desc order
Ans. 
To select 10 records in descending order, use SQL with LIMIT and ORDER BY clauses.
• Use SQL syntax: SELECT * FROM table_name ORDER BY column_name DESC LIMIT 10;

• Replace 'table_name' with your actual table name.

• Specify the 'column_name' you want to sort by, e.g., 'created_at'.

• This query retrieves the latest 10 records based on the specified column.
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Q2. Difference between server side and client side validation
Ans. 
Server-side validation occurs on the server, while client-side validation happens in the user's browser before submission.
• Server-side validation checks data after it is submitted to the server, ensuring security and data integrity.

• Client-side validation provides immediate feedback to users, improving user experience by catching errors before submission.

• Example of server-side validation: Checking if a username already e...read more
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Q3. What is Trimming
Ans. 
Trimming refers to removing unnecessary characters or whitespace from data, often used in string manipulation.
• Trimming is commonly used in programming to clean up user input, such as removing leading and trailing spaces.

• For example, in Python, the method 'str.strip()' removes whitespace from both ends of a string.

• Trimming can also be applied to remove specific characters, like 'str.rstrip('x')' to remove trailing 'x' c...read more
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Q4. How to add multiple values in json .
Ans. 
Adding multiple values in JSON involves using arrays or objects to structure the data effectively.
• Use arrays to hold multiple values: { "fruits": ["apple", "banana", "orange"] }

• Use objects for key-value pairs: { "person": { "name": "John", "age": 30 } }

• Combine arrays and objects: { "employees": [{ "name": "Alice" }, { "name": "Bob" }] }

• Nested structures allow for complex data: { "company": { "name": "TechCorp", "employ...read more
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Q5. Write the JSON format in postman
Ans. 
JSON format in Postman is used to structure data for API requests and responses.
• Use curly braces {} for objects, e.g., {"name": "John"}.

• Use square brackets [] for arrays, e.g., ["apple", "banana"].

• Key-value pairs are separated by a colon, e.g., "age": 30.

• Strings must be enclosed in double quotes, e.g., "city": "New York".

• Example of a complete JSON object: {"user": {"name": "John", "age": 30}}.
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Q6. Diffence between put and patch in potman api
Ans. 
PUT replaces the entire resource, while PATCH updates only specific fields of a resource.
• PUT is idempotent, meaning multiple identical requests have the same effect as a single request.

• PATCH is used for partial updates, allowing you to send only the fields that need to be changed.

• Example of PUT: Sending a complete user object to update all user details.

• Example of PATCH: Sending only the email field to update a user's e...read more
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Round duration - 90 minutes
Round difficulty - Hard

Timing was late evening . Platform was good.

Q1. 
Largest Cycle in Maze Problem Statement
Given a maze represented by 'N' cells numbered from 0 to N-1, and an array arr of 'N' integers where arr[i] denotes the cell number that can be reached from the 'i'...read more
Ans. 
Identify the length of the largest cycle in a maze represented by cells and an array of integers.
• Iterate through each cell and find the cycle length using DFS or Floyd's Tortoise and Hare algorithm.

• Keep track of visited cells to avoid infinite loops.

• Return the length of the largest cycle found or -1 if no cycles exist.
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Round duration - 90 minutes
Round difficulty - Medium

The coding round was 90 minutes with 2 question and the difficulty was mid-range and both were graph question

Q1. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Ans. 
Find all possible paths for a rat in a maze from start to destination.
• Use backtracking to explore all possible paths in the maze.

• Keep track of visited cells to avoid revisiting them.

• Explore all possible directions (up, down, left, right) from each cell.

• Add the current direction to the path and recursively explore further.

• When reaching the destination, add the path to the list of valid paths.
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3 Graph Questions Were asked of difficulty medium to hard.

Hackathon round which revolved around multithreading