Walmart Labs Data Engineer Interview Questions and Answers

Yes

• Knowledge of network protocols and architectures

• Understanding of data structures and algorithms

• Experience with network troubleshooting and analysis

• Familiarity with network security and encryption

• Proficiency in network programming and socket programming

The test went well, I was able to complete all the tasks within the given time frame.

• I prepared well for the test by reviewing relevant materials

• I managed my time effectively during the test

• I was able to solve all the problems and complete all the tasks

• I double-checked my work to ensure accuracy

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

No, as a software engineer, you may not have the necessary experience or skills to work as an IT manager.

• Software engineers typically focus on coding and technical aspects, while IT managers are responsible for overseeing projects, teams, and budgets.

• IT managers need strong leadership, communication, and decision-making skills, which may not be the primary focus of a software engineer.

• Consider gaining experience in pro...read more

OSI stack has 7 layers that define how data is transmitted over a network.

• OSI stands for Open Systems Interconnection

• Each layer has a specific function and communicates with adjacent layers

• Layers are: Physical, Data Link, Network, Transport, Session, Presentation, Application

A router is needed to connect two computers in different networks or to share internet connection.

• When two computers are in different networks, a router is needed to connect them.

• A router can also be used to share internet connection between multiple devices.

• Routers can provide additional security features like firewall and VPN.

• Examples of routers include Cisco, Netgear, and TP-Link.

IPv4 has 32 bits and IPv6 has 128 bits.

• IPv4 addresses are in the format of xxx.xxx.xxx.xxx where each xxx is an 8-bit number.

• IPv6 addresses are in the format of xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx where each xxxx is a 16-bit number.

• IPv6 addresses allow for a much larger number of unique addresses than IPv4.

IPv6 is needed due to the exhaustion of IPv4 addresses and the need for more unique IP addresses.

• IPv6 provides a significantly larger address space compared to IPv4.

• It allows for the allocation of unique IP addresses to every device connected to the internet.

• IPv6 supports improved security features and better network performance.

• It enables the growth of Internet of Things (IoT) devices and services.

• Transitioning to IPv...read more

A /24 address can have 256 clients. Network address is the first IP and broadcast address is the last IP.

• A /24 address has 256 IP addresses

• The network address is the first IP in the range

• The broadcast address is the last IP in the range

Anycast, unicast, and multicast are different ways of routing network traffic.

• Unicast is one-to-one communication between a sender and a receiver.

• Anycast is one-to-nearest communication where the sender sends a message to the nearest receiver.

• Multicast is one-to-many communication where the sender sends a message to a group of receivers.

• Anycast is used for load balancing and finding the nearest server.

• Unicast is used f...read more

Virtual memory is a memory management technique that allows a computer to use more memory than physically available.

• Virtual memory is created by using hard disk space as an extension of RAM.

• It allows running more programs than the physical memory can handle.

• The size of virtual memory is typically larger than the size of main memory.

• Virtual memory is divided into pages, which are swapped in and out of main memory as nee...read more

I rate myself 8 in C and 7 in web technologies.

• I have extensive experience in C programming and have worked on multiple projects using it.

• In web technologies, I have a good understanding of HTML, CSS, and JavaScript, but there is always room for improvement.

• I am constantly learning and improving my skills in both areas.

My strengths include problem-solving skills, attention to detail, and strong programming abilities.

• Strong problem-solving skills - able to analyze complex problems and come up with effective solutions

• Attention to detail - meticulous in writing code and ensuring it is error-free

• Strong programming abilities - proficient in multiple programming languages such as Java, Python, and C++

A generic swap function swaps two values of any data type.

• The function should take two parameters of any data type.

• Use a temporary variable to store the value of one parameter.

• Assign the value of the second parameter to the first parameter.

• Assign the value of the temporary variable to the second parameter.

Search for an element in a rotated sorted linked list.

• Find the pivot point where the list is rotated.

• Divide the list into two sublists based on the pivot point.

• Perform binary search on the appropriate sublist.

• Handle edge cases such as empty list and list with only one element.

Search an element in a rotated sorted array

• Find the pivot point where the array is rotated

• Divide the array into two sub-arrays based on pivot point

• Perform binary search on the appropriate sub-array

• Repeat until element is found or sub-array size is 1

Find 5 missing numbers in an array of size 95 containing numbers in range 1 to 100.

• Create a boolean array of size 100 and mark the present numbers

• Iterate through the boolean array and find the missing numbers

• Alternatively, use a HashSet to store the present numbers and find the missing ones

Given a Sudoku board, find possible numbers for an empty cell.

• Iterate through empty cells and check possible numbers using row, column, and box constraints.

• Use a set to keep track of possible numbers for each empty cell.

• Return the set of possible numbers for the given empty cell.

Find integer average of 4 unsigned integers without typecasting

• Add all the integers and divide by 4

• Use bit shifting to divide by 4

• Handle overflow by using long long data type

• Use unsigned int data type for input

Code to identify 32 bit or 64 bit architecture of a processor

• Check if the operating system is 32 bit or 64 bit

• If OS is 32 bit, processor is 32 bit

• If OS is 64 bit, check if processor supports 64 bit architecture

• Use CPUID instruction to check if processor supports 64 bit architecture

Convert binary number to base 64 integer

• Divide the binary number into groups of 6 bits

• Convert each group of 6 bits to decimal

• Map the decimal value to the corresponding base 64 character

• Concatenate the base 64 characters to form the final integer

I have the skills, experience, and passion to excel in this role.

• I have a strong background in software development, with experience in multiple programming languages and frameworks.

• I am a quick learner and enjoy tackling new challenges.

• I am a team player and enjoy collaborating with others to achieve common goals.

• I am passionate about software engineering and am always looking for ways to improve my skills and knowled...read more

I chose your company because of its reputation for innovation and its commitment to employee growth.

• Your company has a strong reputation for innovation in the industry.

• I was impressed by the emphasis on employee growth and development.

• I believe that your company's values align with my own personal values.

• I was excited about the opportunity to work with a talented team of engineers.

• Your company's mission and vision reso