20+ Product Development Engineer Interview Questions and Answers

Calculate the total amount of rainwater that can be trapped within given elevation map.

• Iterate through the array to find the maximum height on the left and right of each bar.

• Calculate the amount of water that can be trapped above each bar by taking the minimum of the maximum heights on the left and right.

• Sum up the trapped water above each bar to get the total trapped water for the elevation map.

Interview focused on past experiences and hypothetical scenarios, followed by logical, English, and behavioral tests.

• Discussed previous projects, highlighting specific challenges and solutions.

• Explained how I approach problem-solving in hypothetical situations, using the STAR method.

• Demonstrated communication skills through English proficiency tests.

• Showed analytical abilities in logical reasoning tests.

Use two pointers to swap 0s to the beginning and 2s to the end while keeping 1s in the middle.

• Initialize two pointers, one for 0s (left) and one for 2s (right).

• Iterate through the array and swap 0s to the left pointer and 2s to the right pointer.

• Example: Input array = ['2', '1', '0', '2', '1', '0'], Output array = ['0', '0', '1', '1', '2', '2']

Find the first character that repeats in a given string.

• Iterate through the string and keep track of characters seen so far.

• If a character is already seen, return it as the first repeating character.

• If no repeating character is found, return null.

A stack is a data structure that follows the Last In First Out (LIFO) principle.

• Stack is a linear data structure with two main operations: push (adds an element) and pop (removes the top element).

• Overflowing condition for stack occurs when trying to push an element into a full stack.

• A binary tree is a hierarchical data structure where each node has at most two children.

• Depth First Search (DFS) traversal uses a stack data structure to keep track of nodes to visit.

Developing a smart waste management system to optimize recycling and reduce landfill waste in urban areas.

• Implement IoT sensors in waste bins to monitor fill levels and types of waste.

• Use data analytics to optimize collection routes and schedules based on real-time data.

• Create a mobile app for residents to report overflowing bins and track recycling efforts.

• Partner with local recycling facilities to ensure proper waste processing and education.

To swap numbers without using a third variable, use arithmetic operations.

• Add the two numbers to get the first number

• Subtract the second number from the sum to get the second number

• Subtract the original first number from the sum to get the original second number

Use Twitter's public API to extract trending hashtags.

• Authenticate with Twitter API using OAuth 1.0a

• Make a GET request to the trends/place endpoint

• Extract the hashtags from the response and return as an array of strings

To exchange numbers without a third variable, use addition and subtraction operations.

• Add the two numbers to get the sum.

• Subtract the first number from the sum to get the second number.

• Subtract the second number from the sum to get the first number.

Global Interpreter Lock (GIL) is a mutex that protects access to Python objects, preventing multiple threads from executing Python bytecodes simultaneously.

• GIL is a mechanism used in CPython to ensure that only one thread executes Python bytecode at a time.

• It prevents multiple threads from executing Python code concurrently, which can cause issues with thread safety.

• GIL can impact the performance of multi-threaded Python programs, as only one thread can execute Python code at...read more

OOPs concepts like encapsulation, inheritance, polymorphism, and abstraction enhance software design and reusability.

• Encapsulation: A class 'Car' can encapsulate properties like 'speed' and 'fuel' with methods to manipulate them.

• Inheritance: A 'ElectricCar' class can inherit from the 'Car' class, gaining its properties and methods while adding new features.

• Polymorphism: A method 'startEngine()' can behave differently for 'Car' and 'Motorcycle' classes, showcasing method overr...read more

The GD&T symbol for runout is TIR (Total Indicated Runout)

• TIR stands for Total Indicated Runout

• It is used to specify the maximum allowable difference in location of a feature when the part is rotated 360 degrees

• TIR is represented by a circular symbol with two arrows pointing in opposite directions

My favorite subjects in mechanical engineering are thermodynamics, fluid mechanics, and materials science.

• Thermodynamics: Study of energy and heat transfer in mechanical systems. Example: analyzing the efficiency of an engine.

• Fluid mechanics: Study of fluids in motion and at rest. Example: designing a pump system for a manufacturing plant.

• Materials science: Study of properties and behavior of materials. Example: selecting the right material for a specific application.

OOPs concepts include encapsulation, inheritance, polymorphism, and abstraction, crucial for software design.

• Encapsulation: Bundling data and methods in a class. Example: A class 'Car' with attributes like 'speed' and methods like 'accelerate()'.

• Inheritance: Mechanism to create a new class from an existing class. Example: 'ElectricCar' inherits from 'Car'.

• Polymorphism: Ability to present the same interface for different data types. Example: Method 'drive()' behaves differentl...read more

A starter motor is an electric motor used to start an internal combustion engine.

• Used to crank the engine to start it

• Powered by the vehicle's battery

• Engages with the flywheel or flexplate to turn the engine over

• Commonly found in automobiles and other vehicles

DBMS locking is a mechanism to manage concurrent access to data in a database to prevent data corruption.

• Locking is used to ensure data integrity and consistency in a multi-user environment.

• Types of locks include shared locks, exclusive locks, and update locks.

• Example scenario: Two users trying to update the same record simultaneously - one user gets an exclusive lock while the other waits.

• Deadlocks can occur when two transactions are waiting for each other to release locks.

A queue can be implemented using arrays or linked lists. It follows the FIFO principle.

• Create an empty array or linked list

• Enqueue elements at the end of the queue

• Dequeue elements from the front of the queue

• Implement methods like isEmpty, isFull, peek, etc.

• Example: Queue implemented using an array - https://www.geeksforgeeks.org/queue-set-1introduction-and-array-implementation/

Object-oriented programming (OOP) focuses on using objects to design software, enhancing modularity and reusability.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Creating new classes based on existing ones to promote code reuse (e.g., a 'Dog' class inheriting from an 'Animal' class).

• Polymorphism: Allowing methods to do different things based on the object it is acting upon (e.g., a 'draw' method for different sh...read more

LRU cache program is a data structure that stores the most recently used items.

• LRU cache is typically implemented using a doubly linked list and a hashmap.

• When a new item is accessed, it is moved to the front of the list.

• If the cache is full, the least recently used item is removed from the end of the list.

• Example: If the cache has a capacity of 3 and items A, B, C are accessed in that order, the cache will store C, B, A.

• Example: If item B is accessed again, it will move to t...read more

Effective problem solving involves identifying issues, analyzing options, and implementing solutions systematically.

• Define the problem clearly: For example, if a product fails quality tests, specify which tests and criteria are not met.

• Gather data: Collect relevant information, such as user feedback or performance metrics, to understand the issue better.

• Brainstorm solutions: Involve team members to generate a variety of potential solutions, like redesigning a component or cha...read more