HP India ml engineer Interview Questions and Answers

Program to print binary tree elements in spiral order

• Use two stacks to keep track of nodes at odd and even levels

• Push nodes from left to right in odd level stack and right to left in even level stack

• Pop nodes from the stack alternatively and print them

• Repeat until both stacks are empty

Entering a URL in the browser triggers a series of events to retrieve and display the requested webpage.

• The browser checks the cache for a previously stored copy of the webpage

• If not found, the browser sends a request to the DNS server to resolve the domain name to an IP address

• The browser then sends a request to the web server at the IP address for the webpage

• The web server responds with the requested webpage

• The brows...read more

MAC addresses are required for identifying devices on a local network, while IP addresses are used for identifying devices on a global network.

• MAC addresses are used for communication within a local network

• IP addresses are used for communication across different networks

• MAC addresses are assigned by the manufacturer and cannot be changed

• IP addresses can be assigned dynamically or statically

• MAC addresses are used in the...read more

Developed a web application for tracking inventory and sales data

• Used React.js for front-end development

• Implemented RESTful APIs using Node.js and Express for back-end

• Utilized MongoDB for database management

• Integrated authentication and authorization features for secure access

• Designed user-friendly interface with responsive design

An ArrayList is a dynamic array in Java that can grow or shrink in size during runtime.

• ArrayList is a class in Java's Collection framework.

• It implements the List interface and allows duplicate elements.

• Elements can be added or removed using methods like add(), remove(), etc.

• It can also be sorted using the sort() method.

• Example: ArrayList names = new ArrayList<>();

• names.add("John"); names.add("Mary"); names.remove(0);

ArrayList is a resizable array while LinkedList is a doubly linked list.

• ArrayList is faster for accessing elements while LinkedList is faster for adding or removing elements.

• ArrayList uses contiguous memory while LinkedList uses non-contiguous memory.

• ArrayList is better for random access while LinkedList is better for sequential access.

• Example: ArrayList - List names = new ArrayList<>(); LinkedList - List names = new L

Java is not a pure OO language due to primitive types not being objects.

• Primitive types like int, boolean, etc. are not objects in Java

• They do not have methods or inheritance like objects do

• This violates the principle of everything being an object in pure OO languages

• Wrapper classes like Integer, Boolean, etc. were introduced to provide object-like behavior for primitives

Object-oriented languages support inheritance and polymorphism, while object-based languages do not.

• Object-oriented languages allow for the creation of classes and objects, and support inheritance and polymorphism.

• Object-based languages only support objects, but do not have the concept of classes or inheritance.

• Examples of object-oriented languages include Java, C++, and Python, while JavaScript is an example of an obj

Inheritance is a way to create new classes based on existing ones. Abstraction is a way to hide implementation details.

• Inheritance allows a subclass to inherit properties and methods from a superclass.

• Abstraction allows a class to provide a simplified interface to its users while hiding its implementation details.

• For example, a Car class can inherit properties and methods from a Vehicle class, while also implementing i...read more