Walmart Interview Preparation and Recruitment Process

About Walmart

Walmart Inc. is an American multinational retail corporation, founded in 1962 by Sam Walton in Rogers, Arkansas. Headquartered in Bentonville, Arkansas, it’s the world’s largest retailer by revenue, generating nearly $643 billion in global net sales in 2024.

Walmart Interview Questions

It operates over 10,500 stores and clubs across 19 countries, including hypermarkets, discount stores, grocery stores, and warehouse clubs like Sam’s Club. With 2.1 million employees worldwide, it’s also the largest private employer globally.

Key Operations:

* Divisions: Walmart U.S. (largest segment, ~$442 billion in 2023 sales), Walmart International (operates in 19 countries, with Mexico as the biggest market), and Sam’s Club (membership-based warehouses).

* Store Formats: Includes Supercenters (~150,000–260,000 sq ft), Neighborhood Markets (~42,000 sq ft for groceries), and discount stores.

* E-commerce: Walmart.com and platforms like Flipkart in India drive ~$65 million in online sales (2023), boosted by Walmart+ (a membership offering free delivery, fuel discounts, and more).

* Products: Groceries (~60% of sales), general merchandise, apparel, electronics, health products, and private labels like Great Value and Equate.

Business Model:

Walmart’s success hinges on low prices, achieved through:

* Economies of Scale: Massive purchasing power reduces costs.

* Supply Chain Efficiency: Advanced logistics and tech, like AI and robotics, optimize its global supply chain moving 100 billion items yearly.

* Geographic Strategy: Early focus on rural areas created “soft monopolies,” though criticized for impacting small businesses.

Innovations:

* Technology: Walmart Global Tech pioneers AI, machine learning, and generative AI for personalized shopping, waste reduction, and cybersecurity. Autonomous forklifts and “Scan & Go” apps enhance efficiency.

* Sustainability: Achieved a gigaton reduction in supply chain emissions six years early (2024) via Project Gigaton. Targets zero emissions by 2040.

Controversies:

* Labor: Criticized for low wages, anti-union practices, and poor labor rights.

* Bribery Scandal: In 2012, Walmart de Mexico was found to have paid bribes for permits, raising ethical concerns.

* Local Impact: Accused of displacing small retailers, though studies show modest retail job growth.

Social Impact:

* Philanthropy: The Walmart Foundation donated over $1.7 billion in 2024, focusing on community support, disaster relief, and farmer empowerment in India.

* Employee Programs: Offers education via Live Better U and career paths, with 75% of U.S. salaried managers starting hourly.

Ownership & Financials:

* Family-Owned: The Walton family controls over 50% through Walton Enterprises.

* Stock: Publicly traded (NYSE: WMT) since 1970, with stable gross profit margins (~23–25%).

Recent Developments:

* AI Push: Sam’s Club is phasing out traditional checkouts for AI-driven “Scan & Go” nationwide.

* Tariff Talks: Executives met with Trump in 2025 to discuss tariff impacts.

* Anti-Theft: Some stores lock high-value items like steaks and are removing self-checkouts to curb theft.

Walmart Recruitment Process

Interview Process

Now that we've learned a little about Walmart, I'm sure you're tempted to apply for a job there! Because they care so much about their teams and the individuals that make them up, their hiring process is an important aspect of their culture. The goal of Walmart's hiring team is to create a more diverse and inclusive workplace, which starts with employing highly qualified people from varied backgrounds. Walmart's hiring team believes that in order to truly develop for everyone, there must be a diversity of viewpoints and experiences, and a fair hiring process is the first step. To be considered for the job position at Walmart, candidates must go through the following rounds and pass them all:

* Online Assessment

* Technical Interview Rounds

* HR Rounds

All of the rounds listed above are elimination rounds, and you must pass all of them to be considered for the role.

Interview Rounds

1. Online Assessment:

* Taking an online assessment test is the first step in the hiring process. Those who succeed in this phase will be invited to the technical interviews. The online assessment is usually a 90 minutes assessment and includes around 10 MCQs (based on Computer Science fundamental subjects like Object-Oriented Programming, Computer Networks, Operating Systems and Database Management Systems) and three coding questions. The difficulty level of the coding questions ranges from easy to medium to medium-hard.

* To clear this round, have a strong knowledge of the CS fundamental subjects. Also, practice a lot of coding problems as this will help you to clear this assessment.

2. Technical Interview Rounds:

* The technical face-to-face interview is the most important part of the entire hiring process. You will be summoned for a Technical interview if you pass the online assessment test. In this round, the interviewer assesses the candidate’s technical skills and knowledge. Candidates are frequently asked questions based on their resumes and areas of interest during this phase.

* You need to have a thorough understanding of at least one programming language, System Design, as well as computer fundamental subjects such as Object-Oriented Programming (OOPs), DataBase Management Systems (DBMS), Operating Systems (OS), Computer Networks (CN), and be able to explain them to the interviewer. You should also be aware of the latest developing technologies, to achieve a good grade in this round. You must choose and prepare for a field of interest that is directly related to the job. Your problem-solving abilities may be judged during this stage, which may involve puzzles and aptitude tests. Also, be prepared to answer questions about your projects/internships and your involvement in them.

* Candidates at Walmart usually need to undergo 3 rounds of technical interviews. However, the number of technical round interviews may vary depending on your performance in the first round of interviews. You must perform well in all of the rounds in order to increase your chances of getting selected for the next round.

3. HR Interview Round:

* The Human Resources or HR round of the Walmart Recruitment Process is conducted to see if the candidate is a cultural fit for Walmart. In order to ace these interviews, candidates need to study more about Walmart and its products. Here, the interviewer wants to assess you beyond your technical skills. They want to assess your desire and will to join the company. They can also ask about Walmart's history, such as when it was founded, its objectives, values, and goals, as well as its organisational structure.

* Most candidates believe that the HR interview is simple, but keep in mind that a poor HR interview can jeopardise your chances of receiving the job, even if you have cleared all other barriers. The goal is to maintain a pleasant and confident demeanour. Because interviews can be long and dull, remember to smile throughout.

* Candidates may be assigned puzzle-based questions during these rounds to assess their overall intelligence and how well they adapt to difficult and challenging situations. If an applicant fits all of the aforementioned qualifications and has previously shown exceptional technical abilities, he or she will almost probably be employed at Walmart. Some of the questions that may be asked during the Human Resources or HR round are as follows:

* What are some of your strengths and weaknesses?

* What made you want to work at Walmart in the first place?

* What value would you bring to Walmart, and how do you see yourself making a difference in the world while you're working here?

* Is it feasible for you to move to a different part of the country?

* Describe yourself, including who you are and what you know about yourself.

* What was it about Walmart that initially piqued your interest?

* What makes you so special that we should recruit you?

* What are some of the aspects of this career that you find appealing?

* Describe your Final Year Project in detail. What innovative ideas did you offer to this project?

Walmart Interview Questions :

1 .

Implement a binary search algorithm and explain its time complexity.

The binary search algorithm works by repeatedly dividing the search space in half. It starts with the entire array and compares the middle element to the target value. Depending on the comparison result, it narrows down the search space to the left or right half and continues this process until the target element is found or the search interval becomes empty.

#include <iostream>
#include <vector>

int binarySearch(const std::vector<int> &arr, int target) {
int left = 0;
int right = arr.size() - 1;

while (left <= right) {
int mid = left + (right - left) / 2;

if (arr[mid] == target) {
return mid;
} else if (arr[mid] < target) {
left = mid + 1;
} else {
right = mid - 1;
}
}

return -1; // Element not found
}

int main() {
std::vector<int> arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int target = 6;

int index = binarySearch(arr, target);

if (index != -1) {
std::cout << "Element found at index: " << index << std::endl;
} else {
std::cout << "Element not found in the array." << std::endl;
}

return 0;
}

At any Kth step, our search space would be at most N / (2^k), and ultimately, we are required to find the smallest value of K for which it's no longer possible to make further divisions in our search space.
N / (2^k) < 1 on taking log on both sides, we get k = log(N) + 1.

The time complexity of binary search is, therefore, O(logN), which is much more efficient than a linear search time complexity of O(N), especially for large values of N.

2 .

When would you use Stack over Queue?

The time complexity of insertion and removal of elements from both stack and queue takes O(1) time but we have differences in the use cases of both these data structures. We prefer to use a stack when we need to keep track of function calls, manage state changes, or reverse a sequence of elements.

Whereas, we prefer to use a queue when we need to manage tasks in a sequential order, handle items in the order they arrive (e.g., in a print queue or task processing system), or perform breadth-first traversal of data structures.

3 .

Explain the concept of recursion and provide an example.

Recursion is a programming concept where a function calls itself in order to solve a problem. The basic idea behind recursion is to keep breaking down a given problem into smaller and smaller problems so as to ultimately reach a point the original problem has been broken down to such an extent that we know the solution of smallest of sub-problems.

Based on the solution to small sub-problems, we keep building the solution for larger problems until the original problem(largest) is solved. Recursion involves two main components: a base case which is the termination condition of the recursion, when met, it stops the recursive calls and returns a value without further recursive calls. and a recursive case in which the function calls itself with modified parameters, moving closer to the base case. The concept of recursion can be understood with the help of a recursive function which calculated factorial of a number.

#include <iostream>

int factorial(int n) {
// Base case: if n is 0 or 1, return 1
if (n == 0 || n == 1) {
return 1;
} else {
// Recursive case: compute n * factorial(n-1)
return n * factorial(n - 1);
}
}

int main() {
int number = 5;
int result = factorial(number);
std::cout << "Factorial of " << number << " is " << result << std::endl;
return 0;
}

Output: Factorial of 5 is 120Â Â

The factorial function uses recursion to calculate the factorial of a number n. The base case is when n is 0 or 1, in which case the function returns 1. In the recursive case, the function calls itself with n - 1 and multiplies the result by n. This continues until the base case is reached.

4 .

How do you handle null or undefined values in your code to prevent errors?

There are multiple ways by following which we can handle null or undefined values so as to prevent errors. These includes using conditional statements (such as if or switch) to check if a value is null or undefined before attempting to access or manipulate it, providing default fallback values to be used when a variable is null or undefined, using ternary operators to conditionally set a value based on whether a variable is null or undefined, and using try-catch or similar mechanisms to catch exceptions that may arise when working with null or undefined values.

We can also perform type checking to ensure that a value is of the expected type and not null or undefined. We can also use assertions to enforce expectations about values.

5 .

Describe the principles of object-oriented programming and provide an example of inheritance and encapsulation in your code.

The four main principles of OOP includes:

* Encapsulation which focuses on hiding the internal details of an object and providing a controlled interface for interacting with it hence maintaining data integrity and preventing unauthorised access.

* Inheritance which is the mechanism by which one class (subclass or derived class) can inherit the properties and behaviours of another class (super-class or base class) promoting code re-usability and allowing the creation of hierarchies of classes.

* Polymorphism which enables us to write code that can work with objects of multiple types, promoting flexibility and extensibility.

* Abstraction which involves simplifying complex reality by modelling classes based on the essential features and ignoring unnecessary details.

#include <iostream>

// Base class (superclass)
class Shape {
protected:
double area;

public:
Shape() : area(0.0) {}

void setArea(double a) {
area = a;
}

double getArea() const {
return area;
}

virtual void displayArea() {
std::cout << "Area: " << area << std::endl;
}
};

// Derived class (subclass)
class Circle : public Shape {
private:
double radius;

public:
Circle(double r) : radius(r) {
calculateArea();
}

void calculateArea() {
area = 3.14159 * radius * radius;
}

void displayArea() override {
std::cout << "Circle Area: " << area << std::endl;
}
};

int main() {
Circle myCircle(5.0);

// Accessing the inherited area property and overridden displayArea method
std::cout << "Circle's Area: " << myCircle.getArea() << std::endl;
myCircle.displayArea();

return 0;
}

Output:

Circle's Area: 78.5397
Circle Area: 78.5397

In this example, we have two classes: Shape and Circle. Shape is the base class with an encapsulated area property and methods to set, get, and display the area. Circle is the derived class that inherits from Shape and adds a radius property and a calculateArea method. The displayArea method is overridden in the Circle class to provide a more specific implementation.

6 .

Discuss the differences between synchronous and asynchronous programming.

Synchronous and asynchronous programming are two different approaches to managing the execution of tasks and handling the concurrency in a software execution. In synchronous programming, tasks are executed one after the other in a sequential manner. When a task is being processed, it blocks the execution of the other tasks in queue until it's own execution is completed.

Whereas in asynchronous programming, tasks can be initiated and executed independently. When a task takes a long time to complete, the program doesn't wait and continues executing other tasks.
Asynchronous code allows for more effective utilisation of CPU resources, as multiple tasks can run concurrently, making it suitable for applications that require high concurrency, such as web servers and real-time applications. Synchronous code on the other hand do not support concurrency but is relatively easy to understand and predict because it follows a straightforward flow of execution.

7 .

How would you handle and validate user input in a web application?

Handling and validating user input in a web application is essential to ensure the security and reliability of our application. Validation can be achieved in following ways:

* We can employ client-side and server-side form validation to catch errors before they reach the server. HTML 5 provides built-in form validation features that can be utilized on the client side.

* Sanitising the user inputs by removing or escaping potentially harmful characters, such as SQL injection, HTML tags, and JavaScript code.

* When interacting with a database we should avoid embedding user inputs into the SQL queries instead we can use parameterised queries or prepared statements to prevent SQL injection attacks.

* We can employ CAPTCHA or other anti-bot techniques to differentiate between human users and automated scripts.

* We can also implement security headers in your web application to mitigate certain attacks, such as Content Security Policy (CSP) headers.

8 .

What is your approach to debugging complex code issues?

Complex code issues are unavoidable and integral part of software development tackling which can be challenging. To reduce down efforts and efficiently eliminate issues we can:

* Understand the problem and attempt to reproduce it in a controlled environment to identify the specific inputs or conditions that trigger the issue and work accordingly.

* We can isolate the part of code causing the issue by executing different routines individually and disabling all the remaining to identify which block exactly is causing the issue.

* Employ debugging tools provided by your development environment, such as IDEs, debuggers, and profiling tools. Set breakpoints, inspect variables, and dry run through code to understand its execution flow.

* Use version control systems to compare the current code with a previous working version to pinpoint changes that might have introduced the issue.

* Collaborate with a colleague through pair programming to get a fresh perspective on the problem. Sometimes, a second set of eyes can provide valuable insights.

9 .

How can you optimize code performance?

Code performance can be optimised through several ways:

* Selecting efficient data structures and algorithms according to the need of the problem.

* Minimising input/output operations (e.g., file reads/writes, network requests, database queries) to the best extent as possible as they constitute the slowest part during execution.

* Efficiently minimising the number of iterations and reducing work inside loops. Consider loop unrolling and loop fusion where appropriate.

* Implementing caching mechanisms to store frequently accessed data, reducing the need to recalculate or retrieve data from slower sources.

* Compiled languages tend to be faster than interpreted ones. Considering use of languages that compile to machine code for performance-critical parts of the application.

10 .

Consider an SQL table which has name of employees and their salaries as an entry in each tuple. Find the employees who have the second highest salary.

There can be several approaches while writing an SQL query to a particular problem. Be sure that you explain your thinking as and when you are thinking about your approach. This will keep the interviewer engaged and present to him a clearer image of your thinking process.

Approach 1:

SELECT name, MAX(salary) AS salary
FROM employee
WHERE salary IN
(SELECT salary FROM employee MINUS SELECT MAX(salary)
FROM employee);

Here, we first find all the salaries which are not equal to the highest salary. Thus, the highest salary is eliminated by this process. Now, we need to find the employees having the highest salary in the remaining salaries.

Approach 2:

SELECT name, MAX(salary) AS salary
FROM employee
WHERE salary <> (SELECT MAX(salary)
FROM employee);

Here, we use the NOT operator. We run a nested query to first find the highest salary. Then, we find the highest salary in the outer query subject to the condition that it is not equal to the highest salary returned by the inner query.

Approach 3:

select * from employee
group by salary
order by  salary desc limit 1,1;

Here, we use the LIMIT operator. First of all, we order the tuples in the descending order of the salaries. Then we use the LIMIT operator and provide it with an offset value of 1. It implies that we will skip the first entry of the sorted order and limit our results to 1 entry of the remaining result. Here, we make an assumption that all the employees have unique salaries.

11 .

Differentiate between process and thread in the context of Operating Systems.

Process: Processes are programs that are dispatched from the ready state and scheduled for execution in the CPU. The concept of process is represented by the PCB (Process Control Block). Child Processes are created when a process creates another process.

Thread: A thread is a section of a process, which means that a process can have several threads, all of which are contained within the process. There are three states for a thread: running, ready, and blocked.

The following table illustrates the differences between processes and threads in the context of Operating Systems:

Process	Thread
Any program in execution is referred to as a process	A thread is a section of a process.
When a new process is created, we need to load it in the CPU and maintain its state throughout its execution. Thus, a process takes longer to finish.	In the case of threads, we do not need to maintain any state during its execution. This is because its state is maintained by its parent process. Hence, a thread takes less time to finish as compared to a process.
The creation of a process takes more time than that of a thread.	The creation of a thread takes lesser time than that of a process.
In the case of processes, switching between contexts takes longer.	In the case of threads, switching between contexts requires less time.
A process is isolated from other processes.	Memory is shared by threads.
An operating system's interface is used to transition between processes.	Thread switching does not require the use of an operating system and results in a kernel interrupt.
If one process is halted, the execution of other processes is unaffected.	All other user-level threads are blocked if a user-level thread is blocked.
Changes to the parent process have no impact on the child process.	Because all threads in the same process share address space and other resources, any changes to the main thread may have an impact on the behaviour of the process's other threads.

12 .

What do you understand about threads in the context of Operating Systems? What do you know about multi-threading? What are the advantages of multithreading over multiprocessing?

Within a process, a thread is a path of execution. Multiple threads can exist in a process. A thread is the smallest unit of processing and is a lightweight sub-process.

Multithreading refers to the process of running multiple threads simultaneously in a process. By dividing a process into many threads, parallelism can be achieved. Multiple tabs in a browser, for example, can represent different threads. MS Word makes use of numerous threads: one to format the text, another to receive inputs, and so on. Below are some more advantages of multithreading.

The following are the advantages of multithreading:

* Enhanced Responsiveness: Multithreading leads to increased responsiveness in the system. This is because when there are multiple threads, even if some threads get blocked, the other threads may continue their execution.

* Less time to switch context: In the case of threads, context switching is faster. This is because threads share the same data, and code. Only the stacks are different for each thread.

* Increased system utilisation: Let us say that a single processor can have multiple threads. In that case, in a multi-processor system, each process can have multiple threads leading to an effective system utilisation. As a result of this, the throughput of the system increases as well since the number of jobs done per unit time increases.

* Communication: Since all the threads are present within one single process, communication between the threads is much simpler than that of processes.

13 .

What processes are triggered when we type an URL into a browser and hit enter?

Following are the actions taken by the browser whenever we type an URL into a browser and hit enter:

* To find the website's corresponding IP address, the browser scans the cache for DNS entries. It searches for the following cache:

* Browser Cache

* Operating Systems Cache

* Router Cache

* ISP Cache

* If nothing is found in one, it moves on to the next until it is successful. If the domain name is not discovered in the cache, the DNS server of the ISP (Internet Service Provider) performs a DNS query to determine the IP address of the server that hosts the domain name.

* Small data packets, containing the request's content and the IP address it's destined for, are sent.

* The browser uses synchronize(SYN) and acknowledge(ACK) messages to establish a TCP (Transfer Control Protocol) connection with the server.

* The web server receives an HTTP request (either POST or GET) from the browser.

* The server on the host computer processes the request and responds. It generates a response in one of several formats, including JSON, XML, and HTML.

* The server sends out an HTTP response with the response status.

* HTML content is then displayed by the browser.

14 .

What do you understand by wild pointers? How can that be avoided?

Wild pointers are uninitialized pointers that point to any arbitrary memory location, potentially causing a program to crash or behave improperly.

Example : Let us consider the following C program:

int main()
{
  int *temp_pointer;  // A wild pointer
  *temp_pointer = 12; // This corrupts an unknown memory location. This should never be done.
}

In the above example, no memory location is defined for the pointer “temp_pointer” and hence it is a wild pointer. Any random memory location will be assigned to such a pointer and this may corrupt the data present previously on that memory location.

To avoid this, if we want to declare a pointer and we do not have a variable to which we can point the pointer, we can do the following:

int main()
{
   int *temp_pointer = (int *)malloc(sizeof(int)); // Not a wild pointer
  *temp_pointer = 12; // This is fine assuming malloc doesn't return NULL
}

In the above example, we made the pointer “temp_pointer” point to a memory location explicitly allocated for the pointer. This eliminates the risk of corrupting any random memory location.

15 .

What do you understand about the following in the context of DBMS: Primary key, Super key, Candidate key and Foreign key.

* Super Key: The Super Key is a collection of all the keys that help to uniquely identify rows in a table. This means that all columns in a table that are capable of uniquely identifying the table's other columns are called super keys.

* Candidate Key: An attribute or group of attributes that can uniquely identify a tuple such that no subset of it can uniquely identify a tuple, is known as a candidate key. A candidate key can be referred to as a subset of super keys. Among all the candidate keys, one key is chosen and referred to as the primary key.

* Primary Key: A primary key is basically one of the candidate keys. A primary key is a column or group of columns in a table that helps to uniquely identify each record in that table, such that no subset of it can uniquely identify each tuple. In a table, there can only be one primary key. In addition, the primary Key cannot have identical values in any two rows. A PRIMARY KEY (PK) constraint on a column or set of columns prevents null values or duplicates from appearing. There can only be one primary key constraint per table.

* Foreign key: The column in a table that points to the primary key of another table is known as a foreign key. For example - Every employee in a corporation is assigned to a specific department, and employee and department are two distinct entities. As a result, the department's information cannot be stored in the personnel table. That's why the primary key of one table is used to connect these two tables.

16 .

What do you understand by memory leak? How can that be avoided?

When programmers create a heap memory and forget to destroy it, a memory leak develops. The result of a memory leak is that the computer's performance suffers as the amount of usable memory is reduced. In the worst-case scenario, too much of the available memory may be allocated, causing all or part of the system or device to stop working properly, the programme to fail, or the system to significantly slow down. Memory leaks are especially problematic for applications like daemons and servers, which are never terminated by definition.

To avoid memory leaks, heap memory should always be destroyed when it is no longer required.

17 .

Explain the concept of a linked list and its advantages and disadvantages over an array.

Array & Linked List

* A linked list is a data structure that consists of a sequence of nodes where each node contains a value and one/two pointers which points to the adjacent nodes (previous/next). The first element in a linked list is called the head, and the last element typically points to a null reference.

* Compared to array, linked lists can grow or shrink in size during runtime, making them suitable for situations where the number of elements is not known in advance. Apart from that insert and delete operations at any position can be done in O(1) time, whereas in an array it takes O(N) time.

* A major drawback of linked list is that we cannot access an element without traversing the entire list up to that element so random access time is O(N) whereas it is O(1) in case of arrays. Linked list also has poorer cache performance than arrays due to their scattered memory locations.

18 .

What is a hash table and when is it useful in programming?

* A hash table, also known as a hash map, is a data structure that provides efficient data retrieval and storage of key-value pairs. It uses a hash function to compute an index into an array of buckets or slots, from which the desired value can be found.

* They are useful in programming for near-constant-time (O(1)) average-case complexity for key-value retrieval. This is faster than many other data structures, such as arrays or linked lists, which may require linear search. Hash tables can also quickly insert and delete key-value pairs, often in O(1) time. This is particularly advantageous for dynamic data structures that frequently change in size.

19 .

Describe the difference between a breadth-first search (BFS) and a depth-first search (DFS) algorithm.

Breadth-first search (BFS) and Depth-first search (DFS) algorithm

* Breadth-First Search (BFS) and Depth-First Search (DFS) are both graph traversal algorithms used to explore and search through graph or tree structures. They differ in the strategies for visiting nodes and the order in which they explore the graph.

* BFS explores the graph level by level, starting from the source node (or nodes) and moving outward to nodes at the same level before descending to the next level whereas DFS explores down a branch as far as possible before backtracking to explore other branches. It descends as deep as possible along each branch before backtracking.

* BFS uses a queue data structure to maintain the order of nodes to be explored whereas DFS uses a stack. Since we are only iterating over the graph’s edges and vertices only once, the time complexity for both algorithms is linear O(V+E).

20 .

What is dynamic programming, and when would you use it?

Dynamic programming is a problem-solving technique that involves avoiding repetitive calculations by storing the result to be used in future. We break down the given problem into multiple sub-problems. We calculate answer for those sub-problems and store their results so as to avoid calculating it again.

Dynamic programming is helpful in case when the given problem has overlapping sub-problems i.e., there are common sub-problems that are solved multiple times and optimal substructure i.e. solution to a larger problem can be constructed from the solutions to its smaller sub-problems.

This technique can be applied to a wide range of problems, which includes Fibonacci Sequence, Shortest Path Problems, Longest Common Subsequence (LCS), Knapsack Problem, Matrix Chain Multiplication etc.

21 .

How do you handle version control in a team, and what are the benefits of using Git?

* In a team setting, handling version control is essential for collaboration, code management, and tracking changes in the project. A central repository for the project is set up on platforms like GitHub, GitLab, or Bitbucket which serves as the master copy of the code. We define a branching strategy , such as Git Flow, where we have different branches for features, bug fixes, development, and release ensuring all the work is organised and do not interfere with each other.

* Developers are able to clone the central repository to their local machines and work on their assigned tasks in feature branches, making regular commits as they make progress. Once a developer finish working on assigned feature or fix, they create a pull request (PR) to merge their changes into the development branch.

* Git is a popular distributed version control system that offers several benefits for team collaboration. It allows every team member to have their local copy of the entire repository. This enables offline work and faster access to version history. It's branching and merging capabilities allows for work on multiple features or bug fixes concurrently and merge them back into a single codebase. It also allows us to track who made changes, when they were made, and what the changes were, which is essential for debugging and auditing.

22 .

Discuss the basics of RESTful API design.

Designing a RESTful API (Representational State Transfer) involves creating a set of rules and conventions for building web services that are scalable, easy to understand, and work seamlessly with HTTP. Some of the basic principles to follow while designing RESTful APIs include:

* RESTful APIs should use JSON (JavaScript Object Notation) as the format for data exchange. JSON is lightweight, human-readable, and widely supported by programming languages and libraries.

* Endpoints should be logically nested to represent relationships between resources. For example, /users/123/orders would retrieve orders for the user with ID 123.

* RESTful endpoints should use nouns to represent resources rather than verbs. For example, instead of /createUser, we should use /users to represent a collection of users.

* API endpoints should handle errors gracefully and provide informative error responses. Standard HTTP status codes like 400 (Bad Request) and 404 (Not Found) should be used to indicate the outcome of the request to the client.

* RESTful APIs should provide query parameters to allow clients to filter, sort, and paginate data. For example, /products?category=electronics&sort=price&limit=10 could be used to retrieve the first 10 electronics products sorted by price.

* Caching can be employed to improve API performance. By setting appropriate caching headers (e.g. Cache-Control), clients and intermediaries can store responses and avoid redundant requests to the server.

23 .

How does a web server handle client requests and serve web pages?

The web server receives the HTTP request from the client and processes it which typically involves identifying the requested resource (e.g. a specific web page or file) and locating it on the server's file system. In some cases, the web server may need to perform server-side processing, such as running server-side scripts or interacting with a database to generate dynamic content. After the request processing is done the web server generates an HTTP response (can be static or dynamic), which includes an HTTP status code, response headers, and the content of the requested web page or resource. The web server sends the HTTP response back to the client over the established TCP connection. The response includes the requested web page's content and metadata. The client receives the HTTP response and parses the response, rendering the web page and any associated resources e.g. images, style sheets, and scripts.

24 .

What is cross-site scripting (XSS), and how can you prevent it in your web applications?

Cross-site scripting (XSS) is a form of cyber-attack in which an attacker injects malicious scripts (usually JavaScript) into web content that is then viewed by other users. The injected scripts run in the client's machine, potentially leading to various security issues, including data theft, session hijacking etc.

An XSS attack is typically initiated by sending a harmful link to a user and convincing them to click on it. If the application or website doesn't have adequate data sanitation measures in place, the malicious link will execute the attacker's code on the user's system eventually leading to acquisition of user's active session cookies.

For the prevention of XSS in our web application we can employ following methods:

* Input validation must be performed to ensure that it contains only expected and safe data. Any input that looks suspicious, contains HTML or script tags, or exceeds defined limits should be rejected.

* User generated content should be properly encoded before rendering it on web pages. HTML-encode user data to prevent it from being interpreted as code.

* Marking cookies as HTTP-only to prevent client-side scripts from accessing them. This can protect sensitive session data from being stolen.

25 .

Describe the differences between SQL and NoSQL databases and when would you use each.

SQL (Structured Query Language) and NoSQL (Not Only SQL) databases are two different types of database management systems which differ from each other on the organisation of data.

* SQL databases use a structured, tabular format with predefined schemas. Data is organized into tables with rows and columns, and each column has a specific data type.

* NoSQL databases do not has the restriction and support a variety of data models, including document, key-value, column-family, and graph. They are schema-flexible and allow storing unstructured or semi-structured data.

SQL databases are designed for vertical scalability whereas NoSQL databases are designed for horizontal scalability, making them well-suited for applications that need to handle large volumes of data and traffic.

We should use SQL databases when the data structure is well defined and is highly unlikely to change frequently but if there's any scope of evolution or there's need for flexibility we should use NoSQL databases.

26 .

How do you prevent common security vulnerabilities, such as SQL injection and cross-site request forgery (CSRF), in your applications?

Preventing common security vulnerabilities, such as SQL injection and cross-site request forgery (CSRF), is essential to protect our applications from potential attacks. Some of the best practices which eliminates these vulnerabilities includes:

* Employing parameterized queries or prepared statements provided by specific programming language or database framework under use which automatically handles the input data and prevent it from being executed as SQL code.

* Validation of the inputs from the users to ensure that user provided data conforms to the expected formats and does not contain malicious SQL codes.

* Anti-CSRF tokens can be included in the forms which is generated per user session and verified on the server side when form submissions are received.

* Implementing the same origin policy helps to ensure that web pages can only make requests from the same origin from which they were loaded preventing unauthorised requests to other domains.

Frequently Asked Questions

How long does the Walmart interview process typically take?

The duration of the Walmart interview process can vary depending on factors such as the position applied for and the number of candidates being considered. On average, it may take anywhere from a few weeks to a couple of months from application submission to receiving an offer.

Are there any dress code guidelines for interviews at Walmart?

Walmart encourages candidates to dress professionally for interviews. It is recommended to wear business attire or smart casual clothing that reflects your professionalism and respect for the opportunity.

Can I expect behavioral questions during my Walmart interview?

Yes, behavioral questions are commonly asked during Walmart interviews. These questions aim to assess how you handle various situations based on past experiences. Prepare examples that demonstrate your problem-solving skills, teamwork abilities, adaptability, and customer service orientation.

Is having previous retail experience necessary for a software developer position at Walmart?

While having retail experience can be beneficial when applying for certain positions at Walmart, it is not always a requirement for software developer roles. Focus on highlighting your technical skills, problem-solving abilities, and relevant experience during the interview process.

What should I do if I don't know the answer to a technical question during my Walmart coding interview?

If you encounter a technical question that stumps you during your Walmart coding interview, remain calm and honest. It's better to admit that you don't know the answer than to provide incorrect information. Use this opportunity to showcase your problem-solving approach and willingness to learn by discussing how you would find the solution.